Desert Plants Editorial- Fitness and Flexibility a minisymposium

Desert Plants Editorial- Fitness and Flexibility a minisymposium

Volume 2. Number

4. Winter 1980 -81.

Desert

Published by The University of Arizona for the

Boyce Thompson Southwestern Arboretum

Plants

Editorial- Fitness and Flexibility in Relation to Selection and

Propagation of Desert Plants

204

Propagation Techniques for

Desert Plants

205 a minisymposium

Arboretum Progress

217

Robert T. McKittrick

Special Supplement- Living With

Desert Plants Through the Year

219

Sources of Arid Land

Plant Seeds

231

Kent C. Newland

Catastrophic Freezes in the Sonoran Desert

232

Janice E. Bowers

Ferns and Fern Allies of the Garden

Canyon Area of the Huachuca Mountains,

Cochise County, Arizona 237

George Yatskievych

Reviews 244

Fifth Annual Arboretum Plant Sale

245

The Story of Jimson Weed 246

The red -flowered hummingbird -pollinated Silver -Torch Cactus

(Cleistocactus tupizensis) of Argentina growing at the Boyce

Thompson Southwestern Arboretum. When propagated from cuttings of mature plants, flowers appear the first year on the side which had faced the sun. See article on page 205.

204 Desert Plants 2(4)

Winter 1980 -81

Desert Plants

A quarterly journal devoted to broadening knowledge of plants indigenous or adaptable to arid and sub -arid regions, to studying the growth thereof and to encouraging an appreciation of these as valued components of the landscape. Subscription price is $10.00 per year.

Frank S. Crosswhite, editor

Published by The University of Arizona for the Boyce Thompson Southwestern Arboretum

The Boyce Thompson Southwestern Arboretum at

Superior, Arizona, is cooperatively managed by The

Arizona State Parks Board, The Boyce Thompson Southwestern Arboretum, Inc., and The University of Arizona.

Editorial

Fitness and Flexibility in Relation to Selection and

Propagation of Desert Plants. -Population geneticists refer to fitness as the degree to which a population passes on its specialized adaptive heredity unchanged to the next generation. Populations display a type of meristic variation with regard to adaptive characteristics, -a variation which often when graphed produces a "normal curve" with an adaptive peak flanked by less adaptive sides. In any desert situation where rigorous growing conditions change little from year to year, plant populations can be expected to exhibit a high degree of fitness. The rigorous environment tends to truncate the curve fore and aft since the rigor -surviving progeny which live to reproduce are those which fall closest to the adaptive peak.

But although plants must have a high degree of fitness for the present environment, their populations must also exhibit a degree of flexibility to cope with changes in that environment. There is an ever -increasing body of evidence suggesting that climate and growing conditions have indeed significantly changed even in historic times in many of the world's deserts. Generally, as fitness increases, flexibility decreases and vice versa. As a result, each population must strike a balance between fitness and flexibility.

For the short term, a plant population must be fit for the present environment. But for the long term it must be flexible to meet new rigors of some unknown future situation.

Through selection and propagation man is now exploiting the fitness- flexibility balance for his own advantage.

Propagation of plants by man itself implies selection. Man is selecting the plants which will reproduce. Of the hundreds and thousands of plants which are adapted to function and survive under desert conditions, man has selected a small percentage to propagate and use for his purposes.

The fitness of these plants for desert conditions is truly a gift of nature. Plant breeders take the built -in flexibility, often enhance it with hybridization, and select plants with characteristics superior for utilization by man.

Mankind is now becoming the one overpowering agent of change in desert environments. Plant populations with flexibility sufficient to enable them to become commensal with man will survive where man's populations expand in the deserts. Others may pass from threatened and endangered lists to extinction. The Boyce Thompson

Southwestern Arboretum is already a "Noah's Ark" of sorts for a number of desert plants which are either extinct in nature or nearly so.

When man propagates by seed, when a garden situation removes some of the rigors of the environment, or when

"volunteer" plants are of suspected hybrid origin, man commonly rogues through the variable progeny to select types which suit his fancy. In this manner a large number of garden forms of desert plants have been selected over the years, many of which are totally unknown in nature.

Many of these are perpetuated by man for his use through vegetative propagation. This latter process has had a rebirth of interest recently under the name "cloning."

Every plant produced by such a process is identical to the mother plant.

Man in desert areas has the capability of modifying his environment by drawing on the flexibility of natural plant populations, selecting for fitness to meet his own very specific needs, and if necessary perpetuating by clonal propagation. But preservation of entire native desert plant populations having a balance of fitness and flexibility is desirable if for no other reason than to assure an adequate range of germplasm for the future. Just as it would be impossible to preserve all of the brilliance, creativity, genius and genetic potential of the human species by saving only one female and one male for propagation purposes, so too is there a need to preserve a wide range of germplasm of each potentially useful desert plant species.

Insofar as Russian Thistle (Salsola kali) has recently been shown to be useful, perhaps no desert plant should be allowed to become extinct in nature.

Propagation

Techniques for

Desert Plants

Part I of a minisymposium with contributions from

Kent C. Newland

Boyce Thompson Southwestern Arboretum

Sarah Ives

V &P Nurseries, Inc.

Gene E. Joseph and Mark A. Dimmitt

Arizona -Sonora Desert Museum

Marc Mittleman

Desert Botanical Garden

R. E. Foster

Department of Plant Sciences,

University of Arizona

Carol Scannell

Tanque Verde Greenhouses

Department of Plant Sciences Faculty

University of Arizona

W. R. Feldman

Department of Plant Sciences,

University of Arizona

Frank S. Crosswhite

Boyce Thompson Southwestern Arboretum

Chuck Hansen

Arid Land Plants

Minisymposium

Propagation Techniques 205

Recently the journal Desert Plants contacted a number of growers, both commercial and governmental, to see if enough interest existed to assemble a miniature journal symposium dealing with propagation techniques. A large number of persons with expertise in the field shared their knowledge through both written communication and oral discussion. The response was so large and enthusiastic that it seemed desirable to publish a sample of the contributions immediately as Part I and to continue the minisymposium in a future issue.

Under the term plant propagation we ordinarily include any technique by which mankind intentionally increases the number of individuals of a plant. On the other hand, the term plant reproduction is ordinarily used to refer to the natural increase in numbers of individuals. Many times man chooses to propagate a plant by taking advantage of natural reproductive mechanics inherent within the species. Although such propagation is quite common in animal breeding (i.e. bringing two animals together to mate), it is less commonly practiced in propagating plants.

Successful plant growers customarily hire horticulturists adept and knowledgeable at artificial propagation techniques to produce seedlings, rooted cuttings or grafted material which will then be "grown on" to larger size.

Within a company or governmental agency the person with the title "Plant Propagator" is typically greatly respected and may even be held in awe. This person holds the success of the enterprise in his or her hands. The propagator is knowledgable concerning theory, knows a good number of "trade secrets," has a green thumb, and may occasionally be accused of practicing black magic.

Although there may be a number of alternative procedures which would at first thought be capable of yielding similar results, one specific technique may actually prove to be greatly superior. For example, a hard impervious seed coat may be breached by scarifying with a file or sandpaper or grinding wheel, by treating with hot water, by soaking in concentrated sulfuric acid, or by other techniques.

However, the treatment in sulfuric acid has the added advantage of cleansing the seed of any pulp or other material which might be present and of killing fungi and bacteria. Nevertheless, acid treatment may not give as good a result as a hot water soak, depending on the plant.

Seeds are by nature dormant structures. The embryonic plant is already present as well as a food reserve for the early stages of growth. When dormancy is broken and moisture gains entrance into the seed, dehydrated energy in the form of adenosine triphosphate (ATP) goes into solution and triggers rapid changes. Much of the time of the propagator is often devoted to discovering methods of artificially breaking dormancy and causing the ATP to become active. Techniques may be as different as the species are one to the other.

Vegetative reproduction (not involving seed germination) is a time- honored method of quickly obtaining duplicate material identical to the original. There are a great number of procedures varying from tissue culture to rooting cuttings under intermittent mist. Many types of succulent plants, particularly, are propagated vegetatively and there is a wide divergence in methods depending on the species in question.

The Ruby Ball Cactus, a somatic mutant of

Gymnocalycium mihanovichii var. frederickii, provides an excellent example of a plant which must be perpetuated by vegetative means (= cloning). It is propagated by grafting offsets onto a chlorophyll- bearing understock.

This minisymposium brings together a number of previously unpublished findings. It does not take the place of textbooks on the subject and does not purport to be corn plete or encyclopedic. Books previously published which are quite useful are listed below.

References

Brooklyn Botanic Garden. 1957. Handbook on Propagation. Plants and Gardens Vol. 13, No. 2. Special Issue.

Copeland, L. O. 1976. Principles of Seed Science and

Technology. Burgess Publishing Co. Minneapolis,

Minn.

Everett, Percy. 1957. A Summary of the Culture of

California Plants at the Rancho Santa Ana Botanic

Garden, 1927 -1950. Rancho Santa Ana Botanic Garden. Claremont, Calif.

Hartmann, Hudson T. and D. E. Kester. 1968. Plant Propagation, Principles and Practice. Prentice Hall.

Englewood Cliffs, N.J.

Reilly, Ann. 1978. Park's Success With Seeds. Geo. W.

Park Seed Co., Inc. Greenwood, South Carolina.

Schopmeyer, C. S. (ed.) 1974. Seeds of Woody Plants in the

United States. U.S.D.A. Handbook 450.

U.S. Department of Agriculture. 1948. Woody Plant Seed

Manual. U.S.D.A. Misc. Publ. 654.

Wells, James S. 1955. Plant Propagation Practices. Mac-

Millan Publishing Co., Inc. New York.

Wright, R. C. M. 1973. The Complete Handbook of Plant

Propagation. MacMillan Publishing Co., Inc. New

York.

The Baggie© Method of Cactus and Succulent Seed

Germination (Information courtesy of Kent C. Newland,

Boyce Thompson Southwestern Arboretum). Fill 23/a "wide square plastic pots with growing medium of '/3 commercial potting soil, 1/3 coarse sand and 1/3 pumice or perlite. Drench the soil with a solution of Captan® fungicide in distilled water to prevent damping off of the young seedlings. Sow seed in the pots, labelling each with name of the plant, date of sowing and source. Enclose each pot in a plastic Baggie® with a twist tie. This technique simulates greenhouse conditions of high humidity for maximum germination. Shading the pots also seems to benefit germination by simulating low light conditions as found in rock cracks where young cactus and succulent seedlings have been noted.

The seeds will germinate in about two weeks. After the seedlings have made two months of growth, the baggie can be removed. Continue to water. After four or five months the seedlings can be transplanted individually to 2" -wide

Pincushion Cacti of the genus Mammillaria have become popular as flowering greenhouse ornamentals in

Germany, the Netherlands, England, Japan, and elsewhere because they are propagated so readily from seed sent from Mexico and the Southwestern United

States where they are native.

pots and fertilized with Miracle Gro ° The recommended sowing time for cacti is spring, for summer -growing succulents (Euphorbia, Cissus, Adenium) also spring, for winter -growing suc culents (Aloe, Mes embryanthaceae,

Crassulaceae) fall.

Growing Boojum Trees From Seed (Information courtesy of Sarah Ives, V & P Nurseries, Inc., Mesa, Arizona).

To germinate Idria columnaris, collect fresh seed and begin the germination process in May when the older plants are beginning to become dormant. This allows the seedlings to attain a size and vigor sufficient to cope with the May through October dormancy period of the next year. Prepare a soil mix of 1/3 sand, 1/3 peat and 1/3 perlite.

Place this into small seed flats or directly into 21 /a "diameter deep rose pots. Wet the soil and allow to drain.

Use of a fungicide at this stage is optional. If moisture is dispensed to the developing seedlings properly the fungicide will not be needed and if the moisture conditions are not maintained properly the plants will die when the fungicide is leached away anyway.

Place the seed on the damp soil and cover with a layer of soil as thick as the seed. Although the flats or pots can be covered with plastic to keep the soil moist, this is not necessary and may in fact keep the soil too soggy. The seeds germinate within 24 hours and need good ventilation. As the seedlings grow they should be lightly watered but the soil surface should be allowed to dry out.

If the seedlings were started in a flat, once they become somewhat woody they can be separated and planted in individual 23/4"- diameter deep rose pots. During the May to October dormancy period watering should be greatly reduced. This is the most critical period when young seedlings in nature are apt to die. By carefully monitoring the moistness of the soil and by providing optimum greenhouse conditions, a high percentage of the plants will survive this critical period of the first year.

During dormancy the seedlings lose their leaves. Those plants which remain hard and firm will leaf out in the fall but any which become soft and wrinkled should be disposed of.

When the young plants are leafy and growing they can be watered frequently as long as the soil is allowed to dry out between waterings. Use of a fertilizer such as Miracle

Gro° at 1/3 the strength recommended for house -plants can be used every third or fourth watering. The plants thrive on hard greenhouse light and good ventilation.

Home gardeners living where temperatures do not often go below 26 °F should transplant seedlings into the soil when about one year old after they have leafed out from the first dormancy. Screening to protect from rabbits and

208 Desert Plants 2(4)

Winter 1980 -81

Young seedlings of cacti have large fleshy cotyledons under the short plump spiny plant body.

Seedling of Boojum Tree (Idria columnaris).

rodents may be necessary for three to five years. In coastal areas or other regions where fog, humidity and clouds temper the intensity of the sun, plants may be placed in

80% to nearly total sun. In areas with high intensities of light and heat, such as southern Arizona, filtered shade is necessary for young seedlings. When grown at home as a container plant, good filtered light of a patio should prove successful. If the plant must be grown indoors without a greenhouse, a position on the sunniest window -sill should be chosen.

Propagation of Certain Semi -succulent Shrubs of the

Sonoran Desert (Information courtesy of Gene E. Joseph and Mark A. Dimmitt, Arizona -Sonora Desert Museum).

Discussed below are procedures used for propagating the species of Bursera, Fouquieria and Jatropha. BURSERA

SPP.: Burseras are easy to grow once they get past the early seedling stage. Problems are low seed viability and susceptibility of seedlings to fungus until the stems begin to harden a few weeks after germination. Plants grow rapidly if generously potted, but growth slows greatly as soon as the roots become potbound.

Seeds of Bursera laxiflora were collected from cultivated plants at the Arizona- Sonora Desert Museum. Seeds of three other species were collected in Baja California Sur in August of 1979. Seeds were sown in a greenhouse in 1:1 perlite:vermiculite on May 9, 1980. Germination was complete in less than two weeks. Approximate germination was 40% for B. laxiflora, 30% for B. hindsiana, 15% for B. microphylla and less than 5% for B. odorata.

Examination of samples of the same seed collections revealed that most of the seeds were hollow. We surmise that most of the viable seeds germinated. A second collection of B. microphylla sown a few weeks later resulted in about 50% germination. Among seeds collected on the same day from the same plant, darker seeds had higher germination.

During their six weeks in the seed flats the seedlings were treated four times with Banrot° or [email protected] fungicides and fertilized once with full- strength 20- 20 -20.

About 30% of the seedlings succumbed to fungal diseases.

At six weeks the plants were transplanted into 21/4"diameter rose pots, with mortality negligible afterward.

They were treated approximately weekly with Captan

[email protected] or Terrachlor° and fertilized bimonthly for the next seven weeks. In their fourteenth week they were potted up into 4 "- diameter pots, at which time the plants averaged about 8 "tall with basal stem diameters of about

3 /s ". These were grown in 50% shade. Two year old plants in 10 "- diameter pots in full sun now are approaching 3 feet in height with 3/4"-diameter stems.

FOUQUIERIÁ SPP.: The Fouquierias are also fairly easy once past the soft seedling stage, and again some seeds seem to be inviable. Fouquieria splendens grows very slowly even with copious watering and feeding.

Fouquieria macdougalii and F. digueti respond to generous treatment. The former at least will flower in two years, at which time it can be a nicely branched plant 2 feet tall. When grown hard, stem growth is much reduced and the plants develop relatively larger caudexes.

Seeds were sown in flats of 1:1 perlite:vermiculite on

June 8; germination was complete in less than a week.

Approximate germination was 50% for F. digueti and

F. splendens, but only 15% for F. macdougalii. (Seeds collected from cultivated plants of F macdougalii have been found to have much greater viability.) The seedling flats were treated weekly with fungicides named above and fer-

Minisymposium Propagation Techniques

209

A nursery flat full of Fouquieria macdougallii seedlings at the Arizona-Sonora Desert Museum.

tilized with 20 -20 -20 every other week. There was very little mortality. At 6 weeks the plants were moved into

21/4 " -diameter rose pots in well- drained soil and kept in the greenhouse under 50% shade.

JATROPHA SPP.: The Jatrophas are very easy to grow.

The only significant caution is to keep them quite dry during cool weather. In the heat of summer they will grow very fast with generous treatment, or remain as dwarfed bonsai -like specimens if grown hard and/or underpotted.

Seeds of 5 species were planted on June 8 in flats of 1:1 perlite:vermiculite in the greenhouse. Germination was complete within 10 days: species collection number number germiplanted nating j. macrorhiza Southeastern Ariz. 9/78

J. cuneata Hermosillo, Sonora 9/79 j. cerci f oli um

A. S.D.M. (cult.) (10/79

J. vernicosa La Paz, Baja Calif. 1 P79

J. cinerea

Bahia de Los Angeles

Baja California 11/79

4

11

20

5

76

3

71

1

5

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All the seedlings were planted into 3 "- diameter pots in well- drained soil at 3 weeks of age and moved outside under 50% shade 2 weeks later. Fungicides were used weekly until the plants were moved outside. Fertilization is done bimonthly with a balanced fertilizer. Survival has been essentially 100 %. At 10 weeks the j. cinerea and

J. vernicosa plants averaged a foot tall with a basal diameter of about one -half inch. The J. cuneata plants were about 8" tall and 1/2" thick. They probably would be larger if they were in larger pots. These plants have vigorous root systems.

Germination of Agave, Yucca, Nolina and Similar

Plants (Information courtesy of Marc Mittleman, Desert

Botanical Garden, Phoenix). The Desert Botanical Garden has concentrated much of its effort in growing those plants that are not represented in the garden, primarily leaf and stem succulents. We have also placed a large emphasis on growing plants for our plant sales and on growing species that have restricted ranges. Agave arizonica and Agave toumeyana var. bella are two plants in the latter category. These two Agave species were grown from seed planted in October of 1977 and were about ready to go into the ground at the end of 1980.

Yucca glauca, Y. decipiens and Nolina longifolia have also done well from seed. Seeds of these were collected in the summer of 1979 and planted the following January.

Germination occurred anywhere from two to three weeks after sowing. All are now well established in deep 21/4 inch wide liners and are ready to be transplanted up to

1 -gallon cans.

The garden has had great success in starting all of their seeds in a mixture of 50% vermiculite and 50% perlite. As these were started in winter they were set on a heating pad at a temperature of 78 °F. They were watered daily with a fine mist until germination, at which time watering was reduced to every other day. Three weeks following germination, seedlings were thinned and transplanted up to deep 21/4 -inch liners. At the end of 1980 they were ready to transplant up to 1 -gallon cans. The mixture used for transplanting leaf succulents has been that of 2 parts decomposed granite to 1 part each of sand and compost.

About a tablespoon of the 12 -14 month formulation of

Osmocote® fertilizer is added to each gallon can. Aloes,

Dasylirions and many of the Crassulaceae have also responded favorably to these propagation methods.

A Radical Departure in Propagating Prickly Pear Cacti

(Information courtesy of R. E. Foster, Department of Plant

Sciences, University of Arizona). The University of Arizona's planning for an "Energy Ranch" prompted a number of proposals in the realm of renewable energy sources. One of these was the consideration of the Prickly Pear (Opuntia spp.) in a multiple use program. The plant is adapted to desert environments. It has been used for human food and for livestock feed. In some species the potential for rapid and massive growth makes the plant a prime desert candidate for biomass production with either methane or ethanol as an end product. The perennial characteristic suggests uses in erosion control especially in conjunction with land sculpturing for water management. Plantings could be made according to natural water availability. The establishment or renewal of Prickly Pear selections would call for rapid exponential vegetative reproduction.

Quick reproduction is not possible with the accepted methods. All information sources discovered called for the use of mature pads. All suggested that excised pads be allowed to air dry and form callus for about 1 month before being planted for adventitious root development. An extreme change in the time requirement and in other features seemed to call for radical changes in methods.

The procedure developed for vegetative propagation of

When cuttings are taken from large mature cacti with white hair in the form of a cephalium or pseudocephalium, propagants may be induced to not revert to a more juvenile stage if the physiological balance of the piece severed is little disturbed, quickly rooted and given good sun. The plant of

Cephalocereus leucocephalus illustrated here is such a specimen which has continued to produce hairs over a period of several years while grown as a container plant at the Arboretum.

muskmelons was adapted for Opuntia reproduction with surprising success. Various experiments were made.

Research demonstrated that juvenile pads (4 -6 cm long,

3 -4 cm wide, 5 -10 g.) placed in an aerated balanced nutrient solution plus growth regulator woiild start producing roots in 2 -3 days. These plants could be transplanted to soil in 15 -20 days with over 90% success. The results were similar for all species tested. With a spineless ornamental form (used because it was available and easy to handle) the third "vegetative generation" produced roots 170 days after the first padlet was treated. As an interesting spin -off it was found that an Opuntia plant could be grown to -large size with several mature pads in aerated water culture alone. Remember this is a desert loving plant regarding which the admonition if often heard by gardeners not to overwater.

Linda Moore demonstrating the electric carving knife technique at Tanque Verde Greenhouses.

The Electric Carving Knife Technique for Commercial

Cactus Propagation (Information courtesy of Carol Scannell, Tanque Verde Greenhouses). Tanque Verde

Greenhouses in Tucson, Arizona grows and markets cacti and succulents in sufficient quantity to satisfy local retail demands and to fill wholesale requirements of various nurseries and chain stores. Although a large number of cacti are marketed as small plants grown from seedlings, some are grown from cuttings taken from stock plants.

Some of these plants are ones which do not readily produce seeds or do not come true from seed.

When making a large number of cuttings at one time, several factors are important. 1) It is desirable not to have to move stock plants, but rather to cut them in place. 2) It is desirable that the cutting tool have a long blade and long handle. 3) It is good to avoid the "sawing action" of mov-

212

Desert Plants 2(4) Winter 1980 -81 ing the hand back and forth because spines are more apt to pierce the flesh if the hand bumps into a plant. 4) A serrated or sharp edge on the cutting tool is necessary to insure that the vascular bundles are quickly and neatly severed. 5) If fatigue of the fingers develops, efficiency at which consistently good cuttings are produced may decrease.

Although horticultural supply houses market a variety of "cutting knives" or "propagating blades," we have found that an electric carving knife best fills our needs as a commercial grower. By using this device the cuttings are uniform and of consistently high quality. In conjunction with the device, a pair of kitchen tongs (such as are used for grasping hot vegetables from boiling water) is useful for holding the part of the cactus which is being cut away from the stock plant.

Germinating Seeds of Wildland Trees and Shrubs (Information courtesy of Department of Plant Sciences

Faculty, University of Arizona). Many common crops which man has grown over the centuries tend to have seeds with simple germination requirements. Indeed, ease and constancy of germination under agricultural conditions have undoubtedly been selected for in plants which man has grown for a large number of generations. Wildland species, on the other hand, have seeds which often must endure extremely harsh environmental conditions. Such conditions are rarely as optimal for completion of the generalized plant life cycle as are those of the typical cultivated field. Such wildland or "native" plant species have become individually closely attuned to some set of specialized growing conditions.

Indeed, many wildland plants are so well adapted to specific environments that somewhat paradoxically they grow poorly or not at all under less harsh or more generalized conditions. Seeds of wildland plants may exhibit inhibitors or dormancy factors of complex biochemical derivation which are triggered by equally complex ecological sequences.

Seed testing laboratories mantained by governments or private companies are usually set up to deal with standard agricultural species. They will report germination percentages according to established national or international standards. Such testing laboratories often have little time or inclination to experiment with breaking dormancy in non -standard species. Seed testing and germination enhancement for wildland plants have been very capably treated recently in a U.S.D.A. (S.E.A.) publication by

James A. Young, Raymond A. Evans, Burgess L. Kay,

Richard E. Owen and Frank L. Jurak (1978). Previously,

N. T. Mirov and C. J. Kraebel (1939) had published a useful booklet on collecting and handling seeds of wild plants under auspices of the former Civilian Conservation

Corps. Dara Emery (1964) treated seed propagation of native California plants in a leaflet issued by the Santa

Barbara Botanical Garden. Otherwise, information has been quite scarce.

AFTERRIPENING. Some seeds such as those of Saguaro

(Carnegiea gigantea) or Palo Fierro Ironwood (Olneya tesota) germinate readily upon falling to the ground if other factors are favorable. A large number of species, however, may require an "afterripening" period. Often nothing more than holding the seed in a resting stage for six months is required for afterripening. In studies conducted within the Sonoran Desert, data tend to indicate that afterripening may be enhanced by the high ambient air temperatures characteristic of that desert. Investigators working further to the north have described a type of temperature -regulated afterripening whereby seeds of certain species germinate readily at low temperatures but not at medium or higher temperatures until afterripening has occurred. These investigators have found that low temperatures "are more likely to produce germination than higher incubation temperatures for seeds with after ripening requirements." They also point out that low temperatures also reduce growth of harmful microorganisms.

INHIBITORS. Seeds may contain chemical germination inhibitors which must either be washed away with water or leached with organic solvents. The presence of water soluble inhibitors in the seeds of desert plants assures that germination will not occur in nature unless abundant rain has fallen which will allow the seedlings to become well established. When washing inhibitors from seed coats, cold water is usually used because warm water might trigger germination.

SCARIFICATION. Many desert plants have tough impermeable seed coats, sometimes waxy. In nature seeds of

Palo Verde (Cercidium spp.) and several other species of the Legume Family do not ordinarily germinate until they have been washed by flash floods down normally dry washes. After the seeds have become abraded on the sand and gravel of the wash, they begin to imbibe water. If there was not enough rainfall to result in heavy run -off and the seeds travelled only a short distance, the abrasive action may not have been sufficient for water imbibition to occur. Here again an adaptation seems to exist to assure that germination occurs only when environmental conditions favor seedling establishment. To grow such plants under nursery conditions, it may be necessary to artificially scarify the seed coats. Most commercial growers soak the seeds in concentrated sulphuric acid, the length of time depending on the plant species. Other techniques which may prove to be effective but which may take more time and therefore be suitable for only small lots, include holding the seed with a pliars against a grindstone, rubbing the seed against sandpaper, or scratching the seed with a three -cornered file. Care must always be taken to avoid contacting the embryo. Soaking seeds in water which has just been brought to a boil may render the seed coat permeable and may also leach away some inhibitors.

STRATIFICATION. Classically, stratification refers to placing seeds in strata of moist sand outside or in a cold frame over the winter. As stratification is practiced today, seeds are usually placed with moist sand or vermiculite in plastic bags and stored in the refrigerator for one month or more. Growers of the many wild Penstemon species have found that length of time for stratification can be reduced

Minisymposium Propagation Techniques

INITIAL TEST AFTER

COLLECTION

IF SEED GERMINATES NO

FURTHER TREATMENT

11..

AFTERRIPENING

IF SEEDS FAIL TO

GERMINATE OR

IF GERMINATION IS

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TEST TO SEE IF AFTER -

RIPENING IS SATISFIED

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Flowsheet outlining steps for experimenting with germination of seeds of wildland plant species. Courtesy of James A. Young, Raymond A. Evans, Burgess L. Kay,

Richard E. Owen and Frank L. Jurak, from USDA (SEA)

ARM -W -3. By permission.

by placing the moistened seed directly into the freezing compartment of the refrigerator. Most plants of warm deserts do not have seeds which require stratification.

Plants of cold deserts often do, however. Aside from the typical cool -moist stratification, some seeds respond to warm -moist treatments or a combination of warm -moist and cold- moist. Stratification seems to relate to the penetration of oxygen through the seed coat to the embryo.

At colder temperatures oxygen- enriched water becomes available to the embryo and the colder temperatures reduce the oxygen demands of embryonic respiration, resulting in the oxygen -rich environment conducive to germination. Stratification therefor is essentially the same as oxygen enrichment.

CHEMICAL ENHANCEMENT. Chief among chemicals used to enhance germination are 1) thiourea and related sulphydryl compounds, 2) ethephon, 3) nitrate, generally in the form of potassium nitrate, and 4) the growth regulator gibberellic acid. Thiourea is frequently used in a standard three percent solution. [This potentially dangerous chemical should not be used by persons lacking training in use of hazardous chemicals. ] Ethephon functions as an ethylene gas generator, being merely added to the solution or substrate in which the seeds are placed. Potassium nitrate is often used as an 0.2 percent solution. Gibberellic acid up to about 250 ppm can be used in conjunction with the nitrate treatment. The combination of the two is frequently more effective than either substance used alone.

HEAT AND LIGHT. Seeds of different species show different rates of germination at various temperatures.

Although it is possible to determine the optimum germination temperature for a specific species by conducting a large number of separate experiments at different temperatures, a temperature -gradient plate can be used to more rapidly identify the best response. Such a device can be constructed to produce a constant change in tempera-

213

214

Desert Plants 2(4)

Winter 1980 -81 ture from one end to the other and this can be varied by means of manual controls. Seeds are then positioned regularly along the device for inducement of germination.

Some seeds, such as those of Saguaro (Carnegiea gigantea) require light for germination. They are customarily sowed on the surface of flats and a thin layer of chicken -grit broadcast over them. The grit must be widely spaced enough to allow some penetration of light to the seeds. As germination procedes, particles of grit are moved by the emerging seedlings and light penetrates to any individual seeds which previously had insufficient light.

Generally fluorescent light is considered superior to that from incandescent bulbs. In a greenhouse situation, the light entering from outside is sufficient. In growth chambers without natural light, eight hours of artificial light per day is recommended.

REFERENCES. 1) Emery, D. 1964. Seed propagation of native California plants. Santa Barbara Botanical Garden

Leaflet 1(10): 81-96. 2) Mirov, N. T. and C. J. Kraebel. 1939.

Collecting and handling seeds of wild plants. U.S.D.A.

Civilian Conservation Corps. Forestry Publ. No. 5. 3)

Young, James A., Raymond A. Evans, Burgess L. Kay,

Richard E. Owen and Frank L. Jurak. 1978. Collecting, processing, and germinating western wildland plants.

U.S.D.A.- S.E.A. Publ. ARM -W -3.

The Hammer Technique For Breaking Dormancy in

Gourleia (Information courtesy of Sarah Ives, V & P Nurseries, Inc., Mesa, Arizona). The trees of Chilean Palo

Verde (Gourliea decorticans) at the Boyce Thompson

Southwestern Arboretum flower well but produce quite variable and undependable quantities of seed. Although the species is in the Legume Family, the structure of the fruit departs radically from the typical legume pod, being round and fleshy with a hard stone -like center. This modified fruit resembles the drupe characteristic of so many plants in the Rose Family. Some of the seeds produced at the Arboretum are aborted and not suitable for propagation. To identify good seed the fruit can be shaken. A rattle often signifies that a good seed is within. The seed seems not to be attached to the inner woody shell at maturity.

The woody shell is so hard and impervious to water that it must be physically cracked. A hammer can effectively be used to crack the shell. Care must be taken not to crush the seed itself. Sowing can be done in flats and the seedlings transplanted subsequently into rose pots or any other deep container which allows the deep root system to develop. When roots become visible at the drainage holes the plants are ready to transfer to 1- gallon nursery containers.

About half of the seedlings grown from Arboretum seed are usually albino, coming up perfectly white.

Results of Germination Enhancement Trials With Certain Xerophytes (Information courtesy of W. R. Feldman,

Department of Plant Sciences, University of Arizona).

Seeds of arid -land plants were germinated as part of the laboratory portion of a class in nursery management taught in the Department of Plant Sciences. Various experimental treatments to enhance germination have been studied. Some of the data recorded for specific plants are given below. Treatments used in these studies included

1) mechanical scarification with sand paper (MS), 2) acid scarification (AS), 3) immersion in just- boiled water with soaking for 12 hours, or hot water soak (HWS), 4) placing in boiling water and soaking for 12 hours (BWS), 5) cold stratification of imbibed seeds at 35 °F for 6 to 12 weeks

(CS), and 6) no treatment (NT).

Seeds treated by stratification include Ephedra viridis,

Cupressus arizonica, Vitex agnus- castus and Prunus virginiana demissa. Non -treated Ephedra seed had not emerged at 5 weeks, with 60% emergence for those stratified 6 weeks. Vitex seed emerged at the rate of 15% for NT seed and 100% for CS seed stratified for 3 months.

Prunus seed stratified for 3 months had 90% emergence.

Mountain Mahogany (Cercocarpus) had 60% emergence for fresh NT seed in 1977 but only 25% emergence for 1 year old NT seed in 1978. When the 1 year old seed was stratified, however, emergence was 50 %. Cupressus arizonica had 50% emergence for CS seed in 1978. Seed of

Cat's Claw Vine (Macfadyena unguis -cati) planted in early September, 1978, (NT) had very poor emergence until November when night -time temperatures had been in the 40s for 2 or 3 weeks, at which time most of the seed emerged, indicating that they perhaps need a period of cold stratification.

For experiments with scarification, results were as follows: Dasylirion wheeleri, NT= 0 %, MS= 40 %, BWS=

60 %; Cassia artemisioides, MS = 100 %; AS = 90 %; BWS

= 0 %; Pittosporum phillyreoides, NT = 8 %; MS = 90 %;

Rhamnus californica, NT = 15 %, MS = 25 %; Rhamnus crocea var. illieifolia, NT = 10% MS = 15 %; Dodonaea viscosa, NT = 0 %, BWS = 10 %, MS = 100 %; Sophora secundiflora, NT = 0 %, BWS = 0 %, MS = 100 %. Stored seed of either Rhamnus studied may require cold stratification.

Mist -House Propagation of Succulent Euphorbia

Species (Information courtesy of Frank S. Crosswhite,

Boyce Thompson Southwestern Arboretum).

J.

E.

Thompson, Jr., nephew of the founder of the Arboretum, together with scientists at the Boyce Thompson Institute for Plant Research in New York, pioneered studies of adventitious root formation in plants under intermittent mist using growth regulators. This type of propagation is now routine throughout the nursery industry for many woody shrubs and trees as well as herbaceous perennials such as Penstemon. A number of commercial rooting powders or liquids are now available which contain growth regulators in standard concentrations.

Although now a standard procedure for woody species, propagation under mist has not been recommended for succulent plants because of the tendency of cuttings of the latter to become quickly necrotic in a substrate which remains moist for any considerable period of time. During

1972 a large number of succulent Euphorbia tirucalli plants were propagated from cuttings placed into dry soil mix. As is frequently the case with Euphorbia cuttings, rooting was slow and a few cuttings dried up before rooting -out. As watering was slowly increased and the

Minisymposium

Propagation Techniques

215 cuttings were presumably rooting, one particular plant stood out because of its turgidity, dark green, lush growth and generally robust appearance. When it was discovered that the container for this plant was "defective" in that it lacked a drainage hole, the idea was conceived of experimenting with radical departures in rooting Euphorbia cuttings, using the assumption that a moist relatively sterile environment would be desirable.

During 1973, when a large number of Penstemon cuttings were being rooted in the mist -house which remained after J. E. Thompson's studies previously alluded to, representative cuttings from all available Euphorbia species were subjected to experimentation using various mist house routines and growth regulator treatments. One technique resulted essentially in 100% rooting in 2 -4 weeks without necrosis of tissues. This procedure has been used effectively in mass -producing Euphorbias for annual Arboretum plant sales and is described below.

Take apical cuttings of Euphorbia 4 -8 inches long using .

a heavy and sharp pruning shears. Avoid contact of the poisonous sap with eyes or face. Place each cutting into a pail of water as it is taken. When the pail is full, go to a water tap and thoroughly wash latex from the cut surface of each individual cutting. Shake each cutting to eliminate excess moisture and dip the cut end into any of the commercial rooting powders having napthalene acetic acid and/or indole -3 butyric acid. If the preparation does not already include a fungicide, this can be blended -in before use. Place the cuttings into rose pots and fill with clean horticultural grade perlite. Place the pots under intermittent mist.

During cool weather, heating cables or propagating mats may be used to maintain a bottom heat of 70 ° -80 °F. The time clocks should be set to provide a one -second misting every three minutes during daylight hours and a few seconds of misting during widely separated intervals at night.

This method has never failed over several years and has proven quite successful with other genera of the Euphorbiaceae family such as Synadenium and Pedilanthus.

Once the cuttings are rooted they should be removed promptly from the mist -house to avoid hard water encrustations from forming on the stems.

The Shaving Mug and Brush Procedure For Rooting

Cuttings of Large Columnar Cacti (Information courtesy of Frank S. Crosswhite, Boyce Thompson Southwestern

Arboretum). Prepare a mixture of equal parts of 1) powdered sulphur, 2) fungicide powder, and 3) commercial rooting powder. Place into a large mug, adding water to make a thin creamy paste. Take apical cuttings 1 -2 feet long using a pruning saw. Hold each piece being severed with a loop of thick cotton rope. While the surface of the severed piece is still freshly cut, daub the sulphur fungicide- rooting paste onto the surface using an old fashioned shaving brush. As each cutting is treated, turn it on its side to air dry. After a few hours of drying, store each cutting in a vertical position in a plastic nursery container having a thin layer of vermiculite in the bottom. Large heavy cuttings will remain vertical if the cut at the base is perfectly at a right angle to the long axis and the nursery container is chosen to be so snug that the cutting touches on all sides. Cuttings should be stored vertically in 50% to

95 % shade for one month before watering. When watering finally commences, it can be repeated first at weekly intervals, then every 2 -3 days. When the vermiculite has been invaded by a large mass of roots, the cutting can usually safely be planted in a larger container with a good nursery soil mix.

If the cutting is stored horizontally the growing apex will tend to develop a disfiguring right -angle bend. If the cutting is placed directly into soil mix without the month -long callusing period, bacterial necrosis may develop. The sulphur in the paste dries out the cut surface rapidly and sterilizes the wound by forming sulphuric acid on the moist surface. The fungicide kills many of the organisms which might result in necrosis. The rooting powder provides hormonal growth regulators which induce rapid development of adventitious roots.

When cuttings are taken from large mature cacti, the rooted cuttings frequently flower the first year on the side which had faced the sun during the previous winter and spring, irregardless of the new orientation of the cutting (see illustration on cover of this issue). When a cutting of a mature columnar cephalium- bearing or pseudo cephalium- bearing species is rooted, quite frequently hairs of the structure will continue to grow and flowering will occur if the physiological balance of the piece severed is little disturbed, and if the piece is quickly rooted and given good sun.

Propagation and Establishment of Welwitschia mirabilis. (Information courtesy of Chuck Hansen, Arid

Land Plants, Tucson.) Welwitschia is an unusual desert plant of an extremely arid and restricted region of southwest Africa, the Namib. It has been much studied by plant morphologists, anatomists and taxonomists because of its unique structure and position in the plant kingdom. The plant forms two leaves during its lifetime and these lie on the surface of the desert sand with the reproductive structures between them. A plant is said to live one hundred years or more and the old leaves eventually become split into many segments. The plant is of great value in living collections of educational institutions and is a thought provoking conversation piece in private collections. Unfortunately its use has been restricted by knowledge of propagation procedures being not well publicized.

Taxonomically Welwitschia is a member of the Gymnospermae, the group which contains cycads, pines and

Ephedra, seed plants which do not have true flowers.

To propagate Welwitschia, obtain a 6 -inch diameter drainage tile (sewer pipe) of fired red clay to be used as a deep pot. For optimum results the drain -tile should be four feet deep but in any event at least two feet. Choose a clay flower pot that will just fit inside the tile and cement it in place in the bottom of the drain -tile. Place two inches of coarse material in the bottom of the pot and fill the tile with a mixture of 2/3 pumice and a/3 commercial potting soil to a level two inches below the rim. Place a thin layer

B

The unusual gymnosperm Welwitschia mirabilis of the

Namib Desert of Africa, as illustrated in the monograph by A. W. Eichler in Engler and Prantl's Die Naturlichen

Pflanzenfamilien (1889). A: young plant. B: old plant with split leaves. Successful propagation and growth can be achieved by planting in a tall drainage tile to accommodate the deep root.

of pumice (1/2" -1/4") over the soil mix. Water well and let drain. Remove the membranous wing from the seed. Dust the seed with fungicide such as Thiram® and place it directly on the pumice surface. Cover with a 1/2 -inch layer of pumice and mist lightly. Cover the top of the drain -pipe with glass or saran wrap. If the seed is good, germination should occur by one week. Remove the cover when the seedling is well above ground and move the drain -tile into bright light. There is a danger that the rapidly growing root may push the plant out of the soil. If the soil cornpacts at all or if the seed shows a tendency to heave, cover with additional pumice. Do not fertilize the plant for the first four months. Then water with a good well -balanced house -plant fertilizer at one -fourth the recommended strength on the package. Do not fertilize more frequently than once a month during the growing season of spring, summer and fall. The plant does well in the hardest light of a greenhouse. When grown in a home or patio situation, move the drain -tile out -of -doors in the summer and back indoors before the first freeze.

217

Arboretum Progress

Robert T. McKittrick

Boyce Thompson Southwestern Arboretum

McKittrick

Arboretum Progress

This quarterly report will by design lack a central theme and thereby acquaint the reader with a number of developments at the Arboretum.

Admission to the Arboretum

The hours and days during which the Arboretum is open to the public have been changed recently from those in effect since 1972. All of the public facilities of the Arboretum are now open from 8:00 a.m. until 5:30 p.m. daily throughout the year except for Christmas Day. All public facilities are closed on that one day of the year. This is an increase of one hour each day and opens the Arboretum to the public on five holidays previously observed by the staff.

These changes bring the Arboretum's hours of public visitation into conformity with those of all other Arizona

State Parks which have programs which are predominantly interpretive.

In a move entirely unrelated to the above, admission fees were increased to $1.00 per adult visitor. Children

Tinder 17 years of age who visit the park under adult supervision are admitted free. It is hoped that the still nominal fee of $1.00 will significantly increase our revenue from that source and give some relief from our rising costs of operation.

Parking Lot

Desert Plants 2(4182 described the need for improved parking facilities and the master plan solution. The master plan proposes to replace three somewhat separated parking lots with one large one. The new parking lot would be located just inside the highway gate. A new foot trail would provide the visitor with a more beautiful and much less confusing approach to the visitor center and thence to the gardens.

At the September Advisory Committee meeting in 1980 the Boyce Thompson Southwestern Arboretum Board agreed to fund the engineering design for the parking lot.

The Arboretum Board has hired an engineer, soil testing has been accomplished, and a finished design should have been delivered by the time this is published. Cost estimates at that time will determine what future action will be taken.

Research

Comments on the Arboretum's 1979 -80 annual report appearing in Desert Plants 2(4181 touched upon the ground cover study now under way at the Arboretum under the direction of Dr. Charles Sacamano, Extension

Specialist and Horticulturist in the Department of Plant

Sciences of the University of Arizona. Pesented here is a brief but more detailed account of this most interesting and potentially productive study by Dr. Sacamano.

In the spring of 1980 a ground cover evaluation project was established at the Arboretum. Our interest in this group of plants is based on several important characteristics. Ground covers prevent soil erosion by wind and water in both traditional and arid landscapes. They also provide vegetative cover in rocky terrain and on steep, difficult to mow sites. Aesthetically, ground covers unify other design

218

Desert Plants 2(4)

Winter 1980 -81

View of an experimental plot at the Arboretum in which

Dr. Charles Sacamano and Leverett Clark of the

Department of Plant Sciences, University of Arizona, are conducting research on ground covers.

elements and introduce texture, color and scale in the ground surface treatment.

Despite an ever -growing demand for adapted and attractive ground covers, only a limited number of species and cultivars are available commercially in Arizona. Our project at the Arboretum is designed to screen promising ground cover candidates for growth rate, density, erosion control characteristics, heat and cold tolerance, insect and disease resistance, irrigation requirements and year -round appearance. To date, fifteen 3 -ft x 8 -ft plots have been established in the new Arboretum research area. All plots are now planted with test species provided by various western arboreta, Arizona nurserymen and the University of Arizona.

Ground covers that prove adapted and useful in southern Arizona will be publicized and recommended to nurserymen, landscape architects, and when supplies permit, to the home gardening public. A progress report on the performance of the first series of ground cover trials is planned for Fall, 1981.

A new study to collect, characterize and establish arid land legumes at the Arboretum has been authorized with initial funding provided by the Arboretum Board. Dr.

Lemoyne Hogan, Professor of Plant Sciences and Research

Scientist in Horticulture, University of Arizona, will direct this study. He described the study in the following paragraphs.

The Sonoran Desert has many advantages over more temperate, humid areas of the world, including more sunshine, less rainfall and warmer winters which are

Some of the promising ground covers being tested at the

Arboretum.

the primary factors contributing to the area's rapid population growth. However, these same desirable factors are responsible for our greatest problems, including 1) a deficiency of water for conventional irrigated agriculture,

2) the rapid migration of people from colder climates into the area with corresponding competition for scarce water resources.

New crops for agricultural use and for desirable environmental modification, as well as for revegetation purposes on disturbed land must be developed. Only the grasses are more important to man than the legumes.

Members of the Leguminosae family are extensive and the arid members of this family have been greatly under

exploited. There are thousands of little -known arid legume species that should be collected and established for research and study. They have much promise for producing very large increases in food proteins, forage for domestic animals and water conservation under arid urban environments. We in Arizona are in the position to take the lead in the development and utilization of desert legumes. The objectives of this proposal are enumerated below.

1) To assemble seed or other propagules of arid land legumes which are little known in Arizona, but which offer considerable potential for becoming important renewable natural resources in the arid Southwest. 2) To compile information on each introduction as to its requirements, uses and potential. 3) To establish at the

Arboretum either in the research area or public areas those species with the most potential.

(AN ANNUAL READER PARTICIPATION

SUPPLEMENT TO DESERT PLANTS)

Living with

Desert Plants

Through the

Year

AWARDS OF $50 UNITED STATES SAVINGS BONDS.

In general, the major articles published in Desert Plants are written by persons who work with desert plants every day. To provide a forum for increased reader participation, including persons who may or may not work with plants as a profession, this series is being established.

Material submitted for this series should be written in cameo essay style and should be limited in subject matter to some aspect of using desert plants. When an essay is selected and published in the "Livin

With Desert Plants Through the Year" series, the author will receive an award $5- United States Savings Bond. Employees of the Boyce Thompson Southwestern Arboretum may submit essays but are not eligible for the award. Unsigned essays will be produced by the editor. All essays published become the property of the Boyce Thompson Southwestern Arboretum and may be reprinted in book form.

CONTENTS OF THIS ISSUE

Landscaping With Wildlife in Mind

Holding Soil on a Bank With a Feather Duster

A Living Fence of Ocotillo

Attract Hummingbirds by Planting Shrubs and Herbaceous

Perennials Having Flowers in the Red -Yellow Segment of the Color Spectrum

Environmental Restitution as a Hobby

Transplanting Creosotebush

Grow an Extra Room for Fresh -Air Living

Seri Ironwood Carvings

Cut the Heat Load and Cut the Cooling Bill

Heating the House With Wood of Mesquite and Ironwood

Using the Ribs of Saguaro Skeletons

Growing Saguaros and Barrel Cacti From Seed

The Odor of Rotten Meat

Start a Collection of Baskets Made From Desert Fibers

Make a Lamp From Cholla Wood

Bunny Ears in Sheep's Clothing

Don't Let Leucaena From Oaxaca Cause Your Hair to Fall Out

Rather Than Drinking it, Why Not Bake it

For 76 Hours in a Pit in the Ground?

The Jojoba Revolution in Care of Skin and Hair

Using Aloe vera to Treat Burns

Does "Chaparra Tea" Have a Real Value?

It Melts in Your Mouth, Not in Your Hands

The Museum Theory; -- Subject Yourself to a Learning

Experience by Visiting a Museum of Living Plants

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SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

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LANDSCAPING WITH WILDLIFE IN MIND.

Growth of of cities in desert areas and encroachment suburbs into natural plant communities results in destruction of habitat for wildlife.

But even the most densely populated cities eventually develop a fauna linked to the plants which have been used in landscaping.

Where suburbs meet the natural desert or where dwellings have large yards, it is particularly feasible to modify the landscape to attract certain forms of wildlife or to discourage others.

Landowners frequently want to eliminate rattlesnakes and skunks. Skunks often are attracted by an abundance of insects for food, the insects often having been attracted by lights at night.

Rattlesnakes come in where mice, rats and other small animals are abundant.

Cutting down on outdoor lighting and using blackout shades or heavy drapes at windows can reduce the prevalence and crawling insects as well as skunks.

Domestic cats are often kept to keep of flying down the population of mice and rats but they also tend to kill birds, small rabbits and lizards.

Landscaping with plants which do not provide food for mice and rats will select against rattlesnakes as well.

Packrats, rabbits and porcupines can be scourges to desert gardeners.

On the other hand, songbirds, raccoons, squirrels, quail, doves, chipmunks and lizards are considered desirable by many suburbanites.

Although larger forms of wildlife such as deer, mountain lion, and javelina will bighorn sheep, particularly at night, they are far- ranging and little can be done by a bobcat come into suburban areas, small landowner

Desert to keep them on a particular property.

Hackberry (Celtis pal=ida) provides cover for small small wildlife and produces abundant edible fruits.

Saguaro

Cactus

(Carnegiea gigantea) has spines oriented to discourage damage to the plant by javelinas, packrats and rabbits and is an important provider fruit for wildlife in summer.

of

Where rabbits and packrats are abundant it is difficult to grow less spiny forms of cacti, succulents

Desert Penstemon or herbaceous perennials.

(P. parryi) can be used as a free- flowering spring perennial, however, since chewing animals often pass it by.

In general, long lived stiff- branched trees and shrubs are probably best at providing =excess of leaves, twigs and fruits for wildlife while retaining a quantity of biomass necessary to succeed in the landscape.

for the pl ants

Persons desiring to encourage particular forms of wildlife on their property should observe the animals in nature and do some detective work to discover the kinds of plants they use for food and cover.

HOLDING

SOIL

ON A BANK. 'WITH A FEATHER

DUSTER. The desert Feather

'Duster (Calliandra eriophylla) has small leaflets arranged pin of Mesquite.

Innately somewhat like those deed,

Calliandra is often cowboys as

"False

Mesquite" superficial resemblance to prostrate form of referred to by because of a more or a less

Mesquite which grows in

Texas.

The name "Feather more commonly used for

Duster," which is the plant, refers to the pink or whitish flowers with stamens clustered to resemble a miniature feather duster. The plant spreads by means of underground rhizomes to vegetation on hot dry banks. The mat of rhizomes and roots was form a virtual mat of recognized by Arboretum

J. Crider, formerly Head of the

Director F.

Department of Horticulture at the of Arizona, as

University of especial significance for controlling erosion of soil in the

Southwest.

He set up a cooperative nursery to grow and similar soil erosion control this plants at the Arboretum, a nursery staffed by cooperating government agencies.

This proved so successful that the federal government wanted to duplicate it elsewhere on a larger scale.

Crider resigned his position at the Arboretum to become one of the "founding fathers" of of the U.

S.

the Soil Conservation Service

Department of Agriculture.

Partly because of Crider's historic work at the Arboretum with Calliandra and similar erosion - control ground covers, the Arboretum is listed in the

National Register of Historic

Places maintained by the U.S. Department of the

Interior.

A LIVING FENCE OF OCOTILLO.

The Ocotillo

(Fouquíeria splendens) grows in the

Chihuahuan

Desert, Sonoran Desert andMojave

Desert.

It the Middle East, South can also be grown in

Africa, Australia and South America.

The many wand -like branches can be cut two or three making a feet above the ground and used for living fence.

begin.

Late summer is a good time to

In some jurisdictions (particularly

Arizona) a permit may be required to ensure that persons have legal ownership of any

Ocotillos which they cut. It is customary to cut 42 -foot long sections and to weave them with wire to resemble snow- fencing, the redwood lath being replaced by the

Ocotillo wands.

bottom ends of the wands all pointing fence is

Care should be same direction and that taken

The other end will not root.

to have in the the bottom end of the eventually planted in the ground.

As soon as the it is woven, the

Ocotillo fencing should be rolled up like a rug and stored upright in a dry shady place for two weeks to one month.

During this period the cut ends will heal over. While the fencing is curing, the fenceposts should be set into the ground eight to ten feet apart. Two strands of wire are then stretched tight and nailed on the outer side of the posts 12 feet and 3 feet high respecdug tively.

Then a one -foot deep trench is the fence line directly under the length of the wires. The soil removed should to remove roots, gravel and be screened trash, with the best 5/8 in volume saved and mixed with 1/8 sand, 1/8 perlite or pumice and mulch.

1/8 organic

This amended soil is then returned

The cured fencing can then to the to the

Each cane should be allowed to into depth.

trench.

be stretched along the fence line and wired two fence wires already installed.

the amended soil to settle down about one inch in

After two weeks the fence can be

Eventually the fence will lightly watered.

leaf out and new branches will grow at top and bottom.

Mature fences produce flowers.

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

221

ATTRACT HUMMINGBIRDS BY PLANTING SHRUBS AND

HERBACEOUS PERENNIALS HAVING FLOWERS IN THE

RED- YELLOW SEGMENT OF THE COLOR SPECTRUM. In general, the red end of the color spectrum is most visible under (desert) conditions of high light intensities, whereas the blue end is more visible under (non- desert) conditions of low light intensity. In colloquial terms, the "hot" colors are at the red end and the

"cool" colors at the blue end.

There are red, orange and yellow oil globules in the cones of the retina of the hummingbird eye.

These effectively filter out the other colors of the rainbow so that hummingbirds are truly

"colorblind" to colors in the "cool" segment of the spectrum.

Within nature's animal kingdom both insects and birds are noted for feeding on the nectar secretions of flowers.

Within the insect hierarchy, those classed as bees are totally dependent for food on flowers, and within the hierarchy of birds the hummingbirds are equally dependent.

But interesting enough the commonest types of bees respond to the "cool" end of the color spectrum opposite that which attracts hummingbirds .

This allows man to modify his landscape to differentially attract either hummingbirds or bees.

Desert plants which can be used to attract hummingbirds include

Firecracker

Penstemon (P. eatonii). Desert Penstemon (P.

parryi), Chuparosa (Beloperone californicaj,

Desert Honeysuckle ZAni_sacanthus thurberi),

Ocotillo (Fouquieria splendens), Tree Tobacco

(Nicotiana glauca), and the many species of

Aloe.

In the Sonoran Desert hummingbirds used to be absent on migration during the winter because of a scarcity of winter -blooming native food plants.

Importation of Tree

Tobacco from South America and so many kinds of Aloe from Africa have made winter -blooming

Costa's Hummingbird (Calypte costae) pollinbird plants so commonplace that many humming ating Firecracker Penstemon (Penstemon eatoni). Drawing by Carol D. Crosswhite.

birds now spend winters in the Sonoran Desert, failing to migrate.

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SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

ENVIRONMENTAL RESTITUTION AS A HOBBY.

When a home is purchased or newly built or a mobile home placed on a lot, the occupant may wish to restore a portion of the environment to its original condition before bulldozers or construction trucks and heavy equipment modified it. If a person chooses to do this and enough land surrounds the dwelling, it is often possible to divide the landscape into three concentric zones,

1) that nearest the home where native and introduced desert plants with domestic functions are planted, 2) a transition zone, and 3) an outer zone where the original desert has been restored. Often the contractor has planted vegetation in Zone

1 according to specifications of a landscape architect. For Zone 3 to be properly restored a bit of detective work may be necessary to determine the phytosociologic parameters of the original native plant community which once was present.

This phase of landscaping can very effectively be done by the landowner as a hobby over a long period of years.

Persons have done this effectively by studying model desert plant communities at the Boyce

Thompson Southwestern Arboretum.

Aside from several natural Sonoran Desert communities already present, model communities for other deserts are now on the drawing board for construction at the Arboretum. After a property owner has restored Zone 3, various enhancements

This or modifications not honestly fitting into Zone

3 can be established in Zone 2.

area of transition can benefit from desert plants which are not native to the area or from native plants in altered associations.

In this zone, where neither domestic needs nor natural associations are overriding factors, the landowner can experiment and express individuality.

This can be the place to try growing that fascinating plant seen on a vacation or business trip.

TRANSPLANTING CREOSOTEBUSH.

Although it is commonly stated that Creosotebush (Larrea tridentata) can not withstand transplanting, there exist nurserymen with "trade secrets" of how to do it.

A careful investigation reveals that

5- gallon size plants of this species favored by landscape contractors have often been dug.

The very common nature of this plant over so many square miles of Chi huahuan Desert, Sonoran Desert, Mojave Desert, and in South America, makes it a good species to transplant with little fear of making any substantial decrease in its abundance. Nevertheless, persons digging the bushes need permission of the landowner.

Although some of the trade secrets will perhaps always remain secret, some pointers can be given for persons who want to transplant a bush or two from areas where bulldozing is scheduled or from one part of their property to another. Transplanting is most successful from heavy clay soil which will hold together when wet.

The first rule for transplanting Creosotebush is to do it in the winter but to plan for it in summer.

Obtain heavy 5- gallon size plastic pails used in the construction industry.

During summer draw a circle around a small

Creosotebush equal to the pail's diameter.

Pour a bucket of water so that it soaks in within the circle. Repeat in one week.

With a deep and narrow spade the third week cut down at points along the circle a foot or more deep to sever many of the lateral roots.

Continue watering within the circle over the ensuing months to encourage internal root formation within the soil enclosed by the circle and eventually sever all remaining lateral roots.

If the plant looks healthy in mid -winter, cut half of the top away and remove the plant from the ground, making certain that the clay is moist enough to allow the root ball to remain relatively intact.

Place this root ball into the 5- gallon pail, filling any space as well as the top few inches with moist sawdust and fine wood shavings mixed with soil from the hole. Keep wet through the winter.

If the Creosotebush is alive in spring it can be planted safely with very high probability of surviving in its new location.

GROW AN EXTRA ROOM FOR FRESH -AIR LIVING.

Living plant materials can be manipulated just like cement blocks, lumber and other building materials. A blueprint can be drawn up just like that for masonry or wood construction.

For a landscaped "room" to be ready to use, however, it may need some time to grow.

An outdoor room can be furnished with a portable barbecue or a permanent brick fireplace, outdoor chairs, benches, lounges and tables. Or perhaps it could be the focus fora spa or swimming pool. The sides of such a room can be grown by planting the Australian

Acacia stenophylla five feet apart.

A shade roof can be grown by planting a tree of Chilean

Mesquite

(Prosopis chilensis) or Himalayan

Cedar (Cedrus deodara) in the center of the

"room" and cutting enough of the lower branches to allow walking under the spreading boughs.

There are numerous other possibilities which could be obtained from a landscape architect or which could be discovered by personal detective work to fit the particular type of

"room" which the landowner might want and which would be compatible with the land.

SERI IRONWOOD CARVINGS. Seri Indians living on the coast of Sonora, Mexico make beautiful hand - carved items from aged heartwood of

Ironwood (Olneya tesota).

These can be purchased directly from their makers in Mexico or in a few shops in the United States such as the gift shop of the Arizona State Museum operated by the

University of AriLcna in

Tucson. The carvings are usually in the form of various animals known to the Seri and are meticulously sculpted and polished with oil.

The wood is extremely hard, dense, heavy, tight - grained and red -brown in color.

It is so heavy that it will sink in water.

The

Ironwood tree grows in relatively frost -free areas where there is little concentration of cold at night resulting from cold air drainage from higher elevations.

The carvings are so expressive of the character of the wood and the Ironwood tree so characteristic of the

Sonoran Desert that a well- selected carving makes an exceptional conversation piece when used as a table centerpiece at dinner with guests.

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

223

Mesquite (Prosopis velutina) is an excellent food and energy resource of the desert. It not only shades homes to make them cool in summer but lets light and heat through in winter. The hard wood is also a very good source of BTUs when burned. The beans are used as food by man and livestock and the flowers yield a copious nectar which bees store as honey. A: branch with pinnately compound leaves and flower clusters. B: pair of leaflets. C: flower. D: mature bean pods. Drawings courtesy of the College of Agriculture of the University of Arizona.

CUT THE HEAT LOAD AND CUT

THE COOLING BILL.

homes are frequently

In the Sonoran Desert cooled in the summer by refrigeration or by evaporative cooling.

The heat load from the sun can be reduced by painting buildings white, including the roof, the rays of the sun and by intercepting before they strike the

Trees of Mesquite (Prosopis) are building.

very good at shading buildings in the summer and letting the sun's energy through in the winter because, being deciduous, are present in summer the leaves and absent in winter.

the more completely

The colder the winter, deciduous are

Pear cacti the Mesquite trees.

Prickly

(Opuntia spp.) planted near the foundation of- outer house very effectively to walls can serve insulate that portion of the house.

Plants which cut heat loads to conservation are a promote domestic energy current area of investigation at desert research centers.

HEATING THE HOUSE WITH WOOD OF

MESQUITE

AND IRONWOOD.

With energy costs escalating, many desert residents are re- discovering the

BTU's locked up in wood of Mesquite wood. Ironwood dulls saws rather is not as abundant as Mesquite.

and Ironquickly and

Much of the land which supported Ironwood in central and southern Arizona was cut over and converted to Citrus groves and later to housing subdivisions and trailer courts.

Much of the mature Ironwood near civilization has resulted from stump- sprouting of trees cut at of the century for firewood.

the turn

Although Ironwood has apparently declined with increasing settlement, Mesquite has increased dramatically. Mesquite's historic increase is largely due to its being spread by cattle.

As Mesquite is cut for firewood it begins to grow back and so is a valuable renewable natural resource.

It makes one of the very best firewoods of the entire world.

It is good fireplaces and for use in Franklin stoves, outdoor grills.

At the turn of the century

Mesquite was considered valuable for firewood.

With the advent of cheap oil, gasoline, gas and electricity in natural this century, Mesquite became little used for energy and it took on a reputation of being a rangeland pest that was difficult to eliminate.

With Mesquite wood now again commanding a high price, ranchers have the opportunity to sell cutting rights by the cord.

Some jurisdictions now require a permit for the cutting of Mesquite or Ironwood to ensure that persons cutting permission of the landowner to do so.

it have

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

224

USING THE RIBS OF SAGUARO SKELETONS. Since prehistoric times the wooden skeletons of

Saguaro cacti (Carnegiea gigantea), once the plants have died, have been broken apart and the vascular ribs trued up by a little whittling or sanding to be used in construction of walls, fences and ceilings

(often with addition of plaster or stucco) or in making a variety of household items.

They are good for making trellises and shade canopies, or can be used as poles for staking tomatoes; indeed use of Saguaro ribs in desert areas where the plants grow is ubiquitous.

Walk into Pete King's drugstore in Florence, Arizona and look for his diploma or pharmacist's license. Yes, the frame is made from Saguaro ribs.

Encounter a happy retiree enjoying a hike on the desert in the winter sun.

Yes, his walking stick is made from aSaguaro rib.

And what do ranchers prefer to use as spacers in fences between heavy posts?

You guessed it, -- Saguaro ribs.

Saguaro ribs are well suited for making a variety of craft items.

Chances are good that you can think of some entirely new use in your particular situation.

And all who see it will say "Why, you made that from Saguaro ribs, didn't you?

How imaginative!" How many times were those same sentences uttered in prehistoric times, and in how many languages?

Saguaro skeletons with exposed ribs were frequently illustrated in books written by people who had travelled to far -off Arizona in the nineteenth century. The ribs have provided an easily worked wood which has been used by inhabitants of the Sonoran Desert for making various utilitarian articles for centuries.

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

GROWING

SEED.

SAGUAROS AND BARREL CACTI

FROM

A recent article in the Smithsonian magazine focused on digging of cacti such as

Saguaro (Carnegiea gigantea) or Barrel (Fero cactus spp.) and its deleterious effect on the natural desert landscape.

These plants are protected by law in many jurisdictions, particularly in Arizona, but the harvesting of seeds is almost universally allowed.

a hobby,

As indeed even as a "good deed" to nature, persons should be encouraged to produce these plants from seed so that abundant material will eventually be available in future years for landscaping purposes.

Since this takes time, it is a long -term hobby.

Seeds are very abundantly produced by these plants and they germinate readily under proper con dtions.

Barrel cacti have golden fruits which can be twisted off in winter.

Split or cut the fruit open and spread the seeds out on a newspaper in the house to ensure that they are well dried before storage. The fruits of Saguaro split open, naturally fall from the plant in summer, and should be gathered at once so the seeds are not eaten by animals.

Since Saguaro fruits have a moist pulp, the seeds should be washed in water immediately and the clean seeds spread out on newspaper to dry.

225

The Saguaro (right) and Barrel (left) are cacti of the Sonoran

Desert which are not readily propagated from has been recent publicity concerning the cuttings. There illegal digging of them for landscaping purposes without necessary governmental permits.

Although it takes a number of years for these plants to grow large enough for landscaping purposes, they are very easily germinated and grown from seed. Directions are given which should allow a person to grow specimens Zarge enough to plant out in about seven years from seed. Sketch by Carol D. Crosswhite.

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

226

Since some mortality can be expected to occur during the years that will be needed to produce Saguaros and Barrels large enough to use in landscaping, it is advisable to start by germinating a large number of seeds.

A full nursery flat (18" x 18 ") of each species would be a good quantity to germinate.

To do this, build a box large enough to accommodate the number of flats desired on its floor.

The top and bottom should be made of plywood spaced 15 inches apart with all four sides left open to be covered with transparent sheet plastic after the seeds are sown.

Place the box under a Palo Verde or Mesquite tree on the north side of the canopy and begin germination in June or July.

Fill the flats

3/4 full with a soil mix of 1/4 peat moss,

1/4 vermiculite,

1/4 perlite and 1/4 sand.

fertilizer rated

A teaspoonful of slow -release at 8 -9 months duration should the soil of each flat.

be mixed into

Water each flat, let over the drain and sprinkle the seed evenly surface.

Sprinkle a thin layer of chicken grit over the seed so that some seeds still show and the layer is not more than one grit thick.

This can be achieved by watering the seed and grit together with a-misting nozzle on the end of a garden hose. Misting nozzles used in produce departments of grocery stores are about the right type.

The water should form a cloud with absolutely no drip until condensing on the seed and grit.

After settling the seed and grit together, the plastic sheeting should be tacked onto the box to produce a high humidity chamber.

Let the plastic hang free like a window shade on one side weighted down by a length of Saguaro rib stapled to the bottom.

Lift this up once a day to check on humidity and germination, repeating misting when necessary to keep seed moist and humidity high.

When most of the seed is up, cut down on misting, letting plants and soil dry out between waterings.

When seedlings nearly fill the flat, change to watering with a flaring rose nozzle and remove one of the plastic sides of the box.

Nine months after germination, separate the seedlings into clumps of 7 -15 each without disturbing roots within the clumps, then plug into 49 evenly spaced (7 x 7) holes in fresh soil mix in new 18" x 18" flats

(provided with slow-release fertilizer rated at 14 months or more).

A large number of "clump flats" can be produced from one seed flat.

After

14 -18 months, separate the cacti of each clump, placing large ones each into separate 24 -inch diameter square plastic pots and small ones in groups of

2 -3 in

2 -inch diameter pots.

Each succeeding year re -pot into larger containers, from 2 -inch to 24 -inch to 2 3/4 -inch to 4 -inch to 6 -inch (= "one- gallon" size) to

8 -inch or "two-gallon" size. The cacti should be large enough to plant for landscaping in about seven years from germination.

become highly branched and clustered.

Large old specimens are frequently seen on porches in desert regions.

When a person walks by a blooming Stapelia, suddenly the person thinks dead mouse or a piece of that there is a rotten meat somewhere nearby.

who have grown

Stapelia

Even people plants for years forget and may start looking for a dead mouse.

The odor carries for some distance and may completely permeate the air in closed quarters. It may take a long time for the person to associate the smell with the plant. The genus Stapelia and its relatives, rather than attracting bees blooming for pollination by producing nectar and a sweet fragrance, attract flies for pollination by duplicating the odor of rotten meat. The flies lay their eggs on the flower and in so doing carry

Stapelia pollen from the anthers to the

There are numerous relatives of but stigma.

Stapelia which are rare in cultivation in public which are sometimes displayed greenhouses.

Some of these

(moving) structures within the have vibrant flower which resemble writhing fly larvae.

These unusual plant parts further deceive flies into visiting the flowers and in combination with the foul odor guide the insects to the stamens and stigmas.

The genus Stapelia and its relatives are known as "Carrion

Flowers" in

English.

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THE ODOR OF ROTTEN MEAT.

Species of Stapelia from Africa are succulents generally quite attractive to humans in appearance but not in odor.

hairy.

The flowers are often huge and

When protected from frost, plants

Sketch of Starfish Flower (Stapelia nobilis) showing the erect stems, an unopened flower bud and an open putrescent flower.

Sketch by

Carol D. Crosswhite.

SPECIAL SUPPLEMENT LIVING WITH DESERT PLANTS

227

START A COLLECTION OF BASKETS MADE FROM

DESERT FIBERS.

The Papago Indians of the

Sonoran Desert make fine baskets using a coiled foundation of split Beargrass leaves (Nolina microcarpa) sewed with white (sun -bleached)

Yucca leaf strips, green (shade- dried) Yucca leaf strips, and black Devil's Claw (Proboscidea) strips from the fruit.

The sewing is done with either a split open stitch which leaves the Beargrass coils ".risible or a tight closed stitchwhich hides the foundation work.

Apaches make baskets using a foundation of

Never - Break -Bush (Rhus trilobata) stems sewed with strips of Willow (Salix) or Cottonwood

(Populus) bark.

These are frequently made waterproof by calking with Pinyon pitch. Seri

Indian baskets are made from fibers of Torote

(Jatropha), frequently dyed.

Hopi Indian baskets are made by different methods in different villages, including a loose weave of

Yucca for sifting, wickerwork and coiling.

Colorful designs in Hopi baskets are generally achieved by dying the fibrous strips before weaving.

Twill plaited baskets of split Sotol leaves (Dasylirion) are made by the Tarahumara

Indians of Chihuahua, Mexico without decorative colors and are obviously intended for everyday utilitarian use.

Baskets made from desert fibers by North American Indians are becoming less common and good examples command increasingly higher prices from collectors.

MAKE A LAMP FROM CHOLLA WOOD. The skeleton of Jumping Cholla

(Opuntia bigelovii) or

Chain -Fruit Cholla (O. fulgida) is cylindrical and consists of an attractive network of vascular tissue with intervening spaces.

A three -foot long section can be cut from such a skeleton, preferably incorporating some of the wider base of the plant.

The cylinder should be reamed out with a stiff brush attached to a pole.

The outer surface of the cylinder should be sanded with first coarse and then fine sandpaper.

Clean the crevices with the high pressure nozzle of a garden hose and if necessary pass a stiff bottle brush through the many spaces.

Select a board to use as a pedestal for the lamp, cut it to a desired size, do any carving or decorating desired, and drill a half -inch hole in the exact center.

Stretch a lamp cord through the cactus wood cylinder and through the hole in the pedestal.

Then center the bottom of the cylinder on the hole in the pedestal and nail the two pieces of wood together from the bottom of the pedestal. Attach a combination bulb socket and lampshade holder to the upper end of the cord and anchor it onto the upper end of the cholla wood cylinder. Varnish all wooden surfaces to display the g-,:oi n and character of the wood.

Place the l nshade on the holder and an electrical plug on the end of the cord.

Have an electrician or the electrical inspection department of the city or county check the lamp for safety.

After it has been criticized and you have made any suggested improvements, you are all set to make lamps as gifts for friends and relatives.

They make excellent souvenirs of the desert, once not at all uncommon but now rather rarely seen in gift shops.

Plant scientist George Engelmann used this drawing of the wood of Jumping Cholla

(Opuntia bigelovii) to characterize the newly discovered species 125 years ago.

Reproduced from the government document of

1856 entitled "Reports of Explorations and

Surveys For a Railroad From the Mississipi

River to the Pacific Ocean.

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228

SPE -..IAL SUPPLEMENT

LIVING WITH DESERT PLANTS

The Bunny Ear Cactus

(Opuntia microdasys) of the Chihuahuan

Desert has a polka dot pattern of glochids but lacks the long spines which most other species of prickly pear cacti have. Sketch by Carol D.

Crosswhite.

BUNNY EARS IN SHEEP'S CLOTHING. The English name for one of the commonest cacti sold for ornamental use is

"Bunny Ears" (= Opuntia microdasys) , a plant of the Chihuahuan Desert.

The plants are of the prickly -pear type with flat "pad- like" stem segments. A young plant grown from a cutting is normally sold at the stage when two new segments are emerging from the older one, the whole plant then having the appearance of a rabbit's head with ears.

Normal spines areoles are are entirely absent but the filled with many glochids of either white, yellow, chestnut -red, or cinnamon -brown coloration. The glochid patterns make the plants look like stuffed animals covered with polka dot cloth.

Other common

English names which forms of the plant go by are

Yellow

Polka Dots,

White Polka Dots,

Angel Wings, Cinnamon

Bear, or Hob -Nail

Cactus.

A person who has never encountered the species before usually strokes the surface as if petting an animal. Unfortunately, the glochids become embedded in the skin and cause what many persons describe as the most painful itching they have ever experienced.

After an initial encounter, people are loathe to touch the plant again in any way without gloves or tongs. But even among knowledgeable persons it remains a popular ornamental cactus when treated with respect.

communities in Sonora and can also be seen in yards in Arizona in Tucson, Casa Grande,

Superior, Yuma, and less frequently in Phoenix.

The plant has little natural resistance to freezing weather.

Recently, however, scientists have hybridized it with the Texas Lead

Tree (L. pulverulenta) to produce a variety which may possibly become economically important in the horse - latitude deserts which are characteristically colder than the natural home range of Leucaena.

In historic times this Aztec crop was spread through the world`s tropics.

U.

S.

soldiers saw young tender shoots being eaten by Vietnamese.

Leucaena has one drawback which scientists are trying to eliminate.

eaten exclusively

When the plant is without other foods to balance the diet, it causes the hair to fall out.

One sheep rancher in Australia decided to turn this fact to his advantage.

He fed his sheep on Leucaena, after which they could be sheared "with a simple stroke of the hand."

Unfortunately, the separation of the wool from the sheep was so complete that the animals had no protection from the sun and in true "Samson and Delilah" fashion became powerless to cope with their environment.

Readers are referred to the book Ieucaena,

Promising Forage and Tree Crop for the Tropics published by the National Academy of Sciences

(Washington, D.C.) in 1977 for further details of this almost unbelievable happening.

DON'T LET LEUCAENA FROM OAXACA CAUSE YOUR

HAIR TO FALL OUT.

Could this be a

Samson and Delilah story?

The state and city in

Mexico named Oaxaca have long been associated with Leucaena.

Indeed, the name "Oaxaca" is said to be an old Aztec word which can be.

translated

"place where

Leucaena can be found." Leucaena leucocephala is a tall shrub or small tree- in the Legume family.

Like Mesquite, it has pinnately compound leaves with many tiny leaflets.

The young legume pods can be boiled and eaten like

"green beans."

Livestock relish the foliage as a fodder. Leucaena apparently was a IvIeso-

American crop plant long before

Columbus discovered the New World.

It can now be found growing in yards of Latin American persons throughout the warmer parts of the

Americas.

In the desert it is coliuuon in

Branch of Leucaena leucocephala showing a spherical flower cluster in bud, the pinnately compound nature of the foliage, and two mature pods. Drawing by

Carol D. Crosswhite.

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

229

RATHER THAN DRINKING IT, WHY NOT BAKE

IT

FOR 76 HOURS IN A PIT IN THE GROUND?

persons know of the mescal

Most liquor bottled in the

Tequila district of Mexico.

Century

Plant (Agave) species are adapted to sites which are periodically very dry and these plants exhibit numerous "desert plant" adaptations.

The Century Plants are monocarpic, i.e. they flower once and die.

Just before certain kinds flower they are pried out of the ground and the leaves cut away so that only the heart remains, the latter resembling somewhat an oversized pineapple. These hearts are very high in carbohydrate which had been stored to allow growth cf a tremendous flower stalk. A sweet drink from the plant is known as "agua miel."

The juice can be fermented to produce an intoxicating beer -like drink

Distilled beverages are known as

"pulque." marketed under the name "mescal."

In some parts of Mexico a bottle can be purchased

Mescal con su

Proprio labelled

"Legitimo

Giisano."

In the bottom of the bottle is a worm, actually the larva of an Agave- boring insect.

This is added to prove that made from Agave rather than being a the mescal is "legitimo," i.e. that it is really watered down drink adulterated with Sophora or some other substance.

A premium mescal produced from a particular kind of Agave in a certain labelled "tequila," just as a district is particular kind of wine produced in a certain district of France is labelled "burgundy."

Although "mescal" is used as the name of a liquor, the same name is used for a nutritious food which can be produced from hearts of

Agave. Some kinds of Agave make a good mescal food but others are inedible.

Agave murpheyi is easy to grow from bulbils, i.e. little plants produced on the flowering stalk, and may be an ancient Indian cultivar of the Sonoran Desert.

It has been found near prehistoric Indian ruins, being originally discovered as a species new to science growing in a natural area at the Boyce Thompson Southwestern Arboretum.

Mescal food has been experimentally produced at the Arboretum from A. murpheyi using the Indian recipe of baking the heart in a covered pit in the

This slow "cooking" is ground for 76 hours.

done at a temperature low enough so enzymes are not de- activated that but hot enough to cause the carbohydrates to be converted to sugar. If not left in the heated pit long enough the food is reminiscent of sweet potatoes with an after -taste.

When "cooked" longer it tastes more like molasses.

Mescal food cakes similar to ones prepared by the

Tarahumara Indians of Chihuahua in

:istoric time have been excavated from pee. rstoric

Indian ruins in Arizona.

Perhaps scme day

Agave will be developed as a field food crop.

It is very resistant to drought and will grow in deserts with rather low annual rainfall.

Photographs of Agave murpheyi which accompanied the original scientific description of the species in the 1935 volume of the

Contributions From Boyce Thompson Institute photographer.

7

(i):

83 -85. Fred Gibson,

THE JOJOBA REVOLUTION IN CARE OF SKIN AND

HAIR.

Personal cleanliness in Homo sapiens involves the intentional use of water to bathe the skin and wash the hair. Invention of soap and later of various detergents and shampoos had a truly revolutionary impact on human cleanliness. But a relatively insoluble waxy form of "sebum" which is associated with hair follicles may become compacted when only common soaps and shampoos are used.

"Sebum" derives from the Latin name for tallow.

An extreme sebum problem is referred to as seborrhea, but minor problems are apparently' commonplace and have a significant impact on human grooming and appearance.

Recently it was discovered that a liquid wax from Jojoba seeds could be used to break up, dissolve, modify, condition and replace the sebum denosits. Companies which manufacture cosmetics, soaps and shampoos have conducted "proprietary" research, the details of which have been guarded from falling into the hands of competitors, and a number of patents have been issued. Many products in the personal grooming market are now beginning to incorporate Jojoba in their manufacture.

Jojoba enthusiasts believe that a new revolution is now occurring to put human skin and hair care into a third phase following the first phase of water use and the second phase of soap, detergent shampoo use.

The Jojoba plant is shrub native to and a desert the grounds of the

Boyce

Thompson Southwes tern Arboretum. The landmark discovery of the unusual liquid wax in Jojoba seeds resulted from a cooperative research project between the Arboretum and the University of Arizona.

230

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

USING ALOE VERA TO TREAT BURNS.

The scientific name Zr-this plant indicates that it is the "true" (= vera) Aloe used for hundreds of years in medicine. It can be distinguished from other species of Aloe by the combination of its mature leaves being relatively toothless, gray -green, upright and without spots, and its yellow flowers pointing downward.

Many housewives feel that a plant or two of

Aloe vera ought to be grown within a few steps

76T-very kitchen.

Victims of serious burns should see a medical doctor at once, but traditionally Aloe vera has been used as first aid for a wide variety of burns.

One of the thick fleshy leaves is broken open to expose a succulent inner tissue which resembles Jello.

This gel is applied to the burn, care being taken that none of the hard outer part of the leaf scrapes across the burn.

Aloe vera has been used for treating grease burns, sunburn, and even the radiation burns which can result from cancer radiation therapy.

DOES "CHAPARRAL TEA" HAVE A REAL VALUE?

Recently an unusual calcium form of Vitamin -C manufactured at Prescott, Arizona was discussed on television as a possible breakthrough in treatment of arthritis.

Vitamin -C functions as an anti -oxidant but there is apparently some question as to the body's ability to fully utilize it in common chemical non - calcium configurations.

Persons who use "Chaparral

Tea" (actually made from Creosotebush leaves,

Larrea tridentata) for arthritis, rheumatism and as a tonic point out that Larrea leaves contain an unusual anti -oxidant, nordihydroguaiaretic acid (NDGA).

Creosotebush occurs on desert soils having a calcium carbonate

( "caliche ") layer.

Visitors to the Boyce

Thompson Southwestern Arboretum can observe natural "textbook examples" of its presence on calcium carbonate soils and absence from soils not having the calcium carbonate stratum.

Use of "Chaparral Tea" by health enthusiasts deserves further study by medical researchers.

IT MELTS IN YOUR MOUTH, NOT IN YOUR HANDS.

Euphorbia antisyphillitica was named for its use by cowboys and early settlers in the

Chihuahuan Desert and adjacent regions as a supposed preventative of syphillitic infection. In an unusual twist of history it later became used by millions of people in the

United States, Mexico and elsewhere around the world for a quite different reason. Perhaps most readers of this paragraph have consumed a substance from this desert plant.

Where the plant is native in Mexico harvesters make treks out to the hills where it grows and rip it up, roots and all, from the desert.

The plants are bundled and lashed high on the backs and sides of burros to be transported to a camp in the desert where they are boiled in water to which sulphuric acid has been added.

A wax from the plant forms as a scum on the surface.

This is raked off, thrown into buckets and taken to Candelilla wax collection centers to be purified.

This edible wax remains hard under conditions of high heat and humidity as opposed to chocolate and other coverings of candies and confections which stick to wrappers and hands.

Because the wax is water soluble it has been widely used as a covering for pellet -sized gums and candies which "melt in your mouth, not in your hands." Although chocolate bars are popular in cold regions or in winter, the

Candelilla wax covered items have proven more marketable in hot desert regions or in summer.

THE MUSEUM THEORY;

--

SUBJECT YOURSELF TO

A LEARNING EXPERIENCE BY VISITING A MUSEUM

OF LIVING PLANTS.

Botanical gardens and arboretums are classified as museums of living plants.

They teach in a subtle way by means of the museum theory.

It is possible for everyone, from the most ignorant and undereducated child to the most knowledgeable professor or technical researcher to learn more about desert plants and their place in nature's landscape by visiting an appropriate living museum.

A museum is a unique kind of institution devoted to the encouragement of learning and research in a special field of knowledge. When the botanist John Tradescant in England first used the term "museum" in its modern sense for his collection of materials assembled to invite study and research, he resurrected the word from its classical use to describe the temple of the seven daughters of Zeus, each daughter or "Muse" residing there having been regarded in Greek religion and mythology as having the capability of filling a respondent with knowledge in a particular branch of art or science.

The theory behind the establishment of museums is that the objects assembled and displayed fill the visitor with knowledge.

Thus the museum represents the ultimately pragmatic form of education: people will learn or do fruitful research if the very best materials underlying a branch of knowledge are assembled and made available under inviting circumstances.

How better to learn than to be filled with knowledge by materials having a substance so real, pure and attractive as one of the daughters of Zeus! In a museum the materials themselves teach and inspire.

Curators of museums provide structure and guidance to the collection, assemble it, make it available for study, and interpret it.

Such persons, although highly specialized teachers and researchers, are the keepers of the daughters of Zeus and of the temple, providing the circumstances for the union of respondent and

Muse with the intention that the appropriate daughter of Zeus (i.e. the substance of the collection) will be instilled into the communicant to fill that person with true and lasting knowledge of benefit in life. Although it is considered grammatically incorrect to say that a student is learned by a teacher, the unique passive method of teaching which is at the heart of the museum results in the illusion that the museum is "learning the student" because the keepers of the temple are typically lurking behind the scene.

The

Boyce Thompson Southwestern Arboretum strives to be effective as a museum of living desert plants, making available appropriate materials for study by the public and by visiting scientists.

Newland

Sources of Seed

Sources of Arid Land Plant Seeds

Compiled by Kent C. Newland, Boyce Thompson

Southwestern Arboretum

Dieter Andreae

6111 Otzb erg- Tengfel d

Postfach

Heringer WE6

WEST GERMANY

(cactus seed)

Aztekakti

7892 La Grange

El Paso, Texas 79915

(Mexican cactus seed)

Burpee Seed Company

Riverside, Calif. 92502

(flower seed)

Christa's Cactus

529 W. Pima

Coolidge, Arizona 85228

(cactus seed)

Desert Emporium

P.O. Box 26

Warren, Michigan 48090

(cactus seed)

Green Horizons

500 Thompson Drive

Kerrville, Texas 78028

(Texas wildflowers, trees and shrubs)

Gebr. De Herdt

Bolksedijk 3E

B -2310

Rijkevorsel, BELGIUM

(cactus seed)

Karel Knize

P.O. Box 10248

Lima 1, PERU

(S.A. cactus seed)

J. L. Hudson, Seedsman

P.O. Box 1058

Redwood City, Calif. 94064

(worldwide seed)

Gerhard Kohres

Bahnstrasse 101

D -6106 Erzhausen/Darmstadt

WEST GERMANY

(cactus and succulent seed)

Hildegard Nase

2540 E. Ross Place

Tucson, Arizona 85716

(cactus seed)

Native Plants, Inc.

Seed Division Manager

400 Waukara Way

Salt Lake City, Utah 84108

(seed for reclamation, revegetation, forestry)

New Mexico Cactus Research

P.O. Box 787

Belen, New Mexico

(cactus and succulent seed)

Pan -American Seed

P.O. Box 438

West Chicago, Illinois 60185

(wholesale quantities)

231

Geo. W. Park Seed Co., Inc.

Greenwood, South Carol. 29547

(flower seed)

Theodore Payne Foundation

10459 Tuxford St.

Sun Valley, Calif. 91352

(California native plant seed)

Pecoff Bros. Nursery & Seed

Rt. 5, Box 215R

Escondido, Calif. 92025

(environmental restitution)

Jorg Pitz

St- Michael -Strasse 14

Kerpen -Buir

WEST GERMANY

(S.A. cactus seed)

Plants of the Southwest

The Railroad Yards

Santa Fe, New Mexico 87010

(wild trees, shrubs and flowers, SW states)

Clyde Robin

P.O. Box 2855

Castro Valley, CA 94546

(native plant seed from western North America)

Doug Rowland

200 Spring Road

Kempston, Bedford

ENGLAND MK42 8ND

(cactus and succulent seed)

Seeds of the World

P.O. Box 1037

East Nowra, NSW 2540

AUSTRALIA

( Austr. and worldwide seed)

Southwestern Native Seeds

P.O. Box 50503

Tucson, Arizona 85703

(native plant seeds)

Karlheinz Uhlig, Kakteen

D -7053 Kernen 1.R.

Lilienstrasse, 5

WEST GERMANY

(cactus seed)

Windethana Seed Service

Narrikup, W. AUSTRALIA 6326

(Austr. native plant seed)

232

Desert Plants 2(4)

Winter 1980 -81

Catastrophic Freezes in the Sonoran Desert

Janice E. Bowers

Office of Arid Lands Studies

University of Arizona

Introduction

Freezing weather plays an important role in the

Sonoran Desert. The effect of freezing on desert vegetation has been investigated by many workers, including Shreve (1910, 1911, 1912, 1914), Turnage and Hinckley (1938), Hastings and Turner (1965),

Felger and Lowe (1967) and Steenbergh and Lowe

(1976a, 1976b, 1977). The northern boundary of the

Sonoran Desert, defined by the northern extent of characteristic Sonoran Desert plants such as Saguaro

(Cereus giganteus), Triangle -Leaf Bursage (Ambrosia deltoidea), Canyon Ragweed (Ambrosia ambrosioides), Little -Leaf

Palo Verde (Cerdidium microphyllum) and Blue Palo Verde (Cercidium floridum), also coincides with the isotherm beyond which freezing temperatures have occurred which have lasted longer than 24 hours (Hastings, 1963).

Duration and intensity of freezing temperatures determine the northern and eastern extent of Sonoran

Desert vegetation (Shreve, 1914; Turnage and

Hinckley, 1938).

Saguaro populations at the eastern margin of the

Sonoran Desert have undergone demographic changes as a result of recurrent severe freezes between 1913 and 1971 (Steenbergh and Lowe, 1976a,

1976b, 1977). Steenbergh and Lowe conclude that severe freezes which kill large numbers of very young and very old individuals of Saguaro were not characteristic of the environment for 50 to 100 years before 1890. Catastrophic freezes damage or kill many other species as well, both at the margins of the Sonoran Desert and occasionally well into its center ( Turnage and Hinckley, 1938; Jones, 1979).

During the past 100 years, the climate of the

Southwest has become warmer and drier (Leopold,

1951; Hastings and Turner, 1965; Cooke and Reeves,

1976). Thus, subtropical plants in the Sonoran

Desert in Arizona must either adapt to more xeric conditions and to recurring catastrophic freezes or be eliminated by drought and frost. Although it might seem that catastrophic freezes should cause the boundaries of the Sonoran Desert to shift to the south and west, the general trend toward a warmer and drier climate tends to prevent higher- elevation species from moving downslope to occupy the vacated habitat. It is possible that the margins of the

Sonoran Desert have not dramatically shifted geographically, but that the composition and structure of plant associations at the margins have changed markedly due to the combined effects of catastrophic freezes and a more xeric climate.

Although many researchers have studied freezing in the Sonoran Desert, none have examined longterm weather data to determine the combined ef-

Bowers

Catastrophic Freezes 233 fects of freezing temperatures and duration of freezing on Sonoran Desert vegetation. This present paper will fill that gap by 1) defining catastrophic freezes in biological and climatological terms, and

2) correlating temperature records with observed catastrophic damage to Sonoran Desert plants during this century.

Methods

Since Steenbergh and Lowe (1976a) have stated that temperatures below 21 °F are critical to survival of Saguaro, I tallied the number of nights since 1894 when temperatures at the University of Arizona weather station in Tucson fell below 21 °F. In addition, I compiled hourly temperature data from

Tucson International Airport for winters between

1946 and 1979. [The hourly observations include data from January, 1946 to February, 1949; December, 1952 to December 1957; January, 1962 to

January, 1979. Temperature observations were made at 3 -hour intervals from January, 1965 to

January, 1979.] I also searched the literature for references to catastrophic freezes and frost damage to

Sonoran Desert plants. These references were compiled into a chronology of catastrophic freezes in the

Sonoran Desert (Appendix 1).

Results and Discussion

Winter temperatures fell below 21 °F in Tucson 86 times between 1894 and 1979. Catastrophic freezes in which a wide variety of native plants over large areas of Sonoran Desert were killed or severely damaged were less frequent, only nine such freezes occurring between 1894 and 1979 (Appendix 1). Apparently, although freezing temperatures below 21 °F kill juvenile and very old individuals of Saguaro (and possibly other Sonoran Desert plant seedlings as well), more severe conditions are necessary for catastrophic damage to occur. The problem, then, is to define catastrophic freezes in climatologic terms by discovering the combinations of low temperature and duration of freezing which cause catastrophic damage to Sonoran Desert plants.

Hourly temperature observations for 325 nights show that temperatures below 33 °F at the Tucson

International Airport lasted no longer than 9 hours on 85% of the nights, for 10 -15 hours on 14% of the nights, and for 16 hours or longer on only 2% of the nights. Similarly, temperatures above 24 °F occurred much more frequently than temperatures below

24 °F. On 90% of freezing nights the minimum temperature was 25 °F or higher (Figure 1). Hourly temperature observations also demonstrate that minimum temperature is loosely associated with duration of freezing (Figure 2). Minimum temperatures of 28 °F to 32 °F are most frequently associated with a relatively short period of freezing (1 -9 consecutive hours) and minimum temperatures of 20 °F to 26 °F are more frequently associated with a longer period of freezing (12 -20 consecutive hours). The general pattern which emerges from these data is that most freezes in Tucson are brief and not very intense. The few freezes that are very cold also last longer.

Hourly temperature data correspond well with the biologically defined catastrophic freezes listed in

Appendix 1. In most cases catastrophic freezes occurred when the lowest temperatures and the longest durations of freezing coincided (Table 1). For example, a freeze lasting 11 hours and reaching a minimum temperature of 22 °F was recorded on February 4, 1955. This freeze was apparently not catastrophic. However, on January 11, 1962, a freeze with the same minimum temperature but lasting 19 hours was catastrophic. On January 17, 1949, freezing temperatures lasted for 15 hours, but the minimum at the airport never fell below 31 °F. A later freeze on January 6, 1971 also lasted for 15 hours, but the minimum temperature was 18 °F. The 1949 freeze was not catastrophic but the 1971 freeze was.

Table 1. Duration of some freezes at Tucson International

Airport, 1946 -1979. Data are from U.S. Weather Bureau,

Local Climatological Summaries, Tucson, Arizona.

Date

Jan. 28, 1948

Jan. 29, 1948

Jan. 4, 1949

Minimum

Temp.

( °F.)

26

26

17

Duration

(Hours

32 °F.)

14

13

20

Remarks

Catastrophic

(see Table 1)

Jan. 5, 1949

Jan. 17, 1949

Jan. 18, 1949

Jan. 30, 1949

Dec. 28, 1954

Feb. 4, 1955

Jan. 11, 1962

17

31

26

26

18

22

22

14

13

11

19

16

15

12

Catastrophic

(see Table 1)

Jan. 12, 1964

Jan. 4, 1971

19

18

12

18

Catastrophic

(see Table 1)

Jan. 5, 1971

Jan. 6, 1971

Jan. 7, 1971

Jan. 8, 1971

Jan. 9, 1971

Dec. 24, 1974

Dec. 8, 1978

19

17

20

20

26

19

20

12

12

18

18

15

15

12

Catastrophic

(see Table 1)

Dec. 9, 1978 23

15

234

Desert Plants 2(4) Winter 1980 -81

27

26

25

32

31

30

29

28

24

23-1.11

22

21

20 AM

19-111

181

17 -11

0 10 15

20

Number of Nights

Figure 1. Number of freezing nights at Tucson

International Airport, 1946 -1979. Data are from U.S.

Weather Bureau, Local Climatological Summaries,

Tucson, Arizona.

45

Other characteristics of these particular freezes are also worth nothing. First, the overnight freeze on

January 17, 1949 was preceded and followed by nights that were not unduly cold. On the other hand, the catastrophic freeze of January 6, 1971 occurred on one of four consecutive nights of very cold weather. This is characteristic of the catastrophic freezes. Secondly, minimum temperatures vary from place to place across rather small distances. During the catastrophic freeze of January 11 -12, 1962, the minimum temperature both nights was 22 °F at

Tucson International Airport, 7 miles south of the

University of Arizona. At the University, the minimum was 24 °F on January 11 and 20 °F on January

12. The minimum temperatures were 20 °F and

15 °F on January 11 and 12, respectively, at the

Campbell Avenue Farm, only 4 miles north of the

University of Arizona.

50 55 60

Catastrophic freezes usually occur within 17 days of the winter solstice. Since there are more hours of potentially freezing darkness and fewer hours of relatively warm daylight during this winter solstice period, it seems likely that cold fronts moving into the Sonoran Desert on or about December 21 will be harsher than they would be in early December or late February. The longer nights mean that cold temperatures will be prolonged, occasionally with catastrophic results to native plants.

Summary

In the Sonoran Desert there is a gradient from mild freezes with little effect on native plants to severe freezes which inflict damage to frost sensitive plants (such as juvenile or very old individuals of Saguaro), to catastrophic freezes which kill or injure many species of plants over large areas.

65

Bowers Catastrophic Freezes

235

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

I Lowest recorded minimum

® Average minimum

ß 3 4

5 6 7 8

10

11

12

Number of Hours

13

14

Figure 2.

Correspondence of minimum temperatures with duration of freezing at Tucson International Airport,

1946 -1979. Data from source in Figure 1.

15 116 1

17 18

19 120

Severe freezes are less frequent than mild freezes and catastrophic freezes are less common yet. Catastrophic freezes have occurred more frequently during the last 100 years than in the previous century and may have modified the structure and species composition of plant associations on the margin of the Sonoran Desert. An analysis of hourly temperature observations shows that catastrophic freezes occur when low minimum temperatures and many consecutive hours of freezing interact. Between 1946 and 1979, there were four freezes which lasted between 15 and 20 hours, reached minimum temperatures between 17 °F and 22 °F, and caused widespread frost damage to Sonoran Desert plants. These were catastrophic freezes.

Appendix 1. A Chronology of Catastrophic Freezes in the Sonoran

Desert.

January, 1913. Minimum Temperature: 6 °F in Tucson, 16 °F in

Phoenix, 11 °F in Florence. Duration: 19 hours in Tucson; low temperatures "extended over a considerable portion of the night preceded by nearly 24 hours of continuous freezing weather."

Observations of Damage to Plants: "Thousands of small giant cactus plants growing near their greatest altitudinal limits were killed outright. Many other species also suffered great damage."

Source: Turnage and Hinckley, 1938; Thornber, 1916.

January, 1937. Minimum Temperature: 10 ° -20 °F in desert areas; 15 °F in Tucson, 20 °F in Altar, Sonora; 16 °F in Carbo,

Sonora; frost reported in Kino Bay, Sonora. Duration: 19 hours at

Tumamoc Hill in Tucson; in addition the 1937 cold wave

"lingered over an entire week." Observations of Damage to

Plants: Between Sells and Ajo, Olneya tesota, Celtis pallida,

Ambrosia ambrosioides, Jatropha cardiophylla, Encelia farinosa,

Sapium biloculare and Cereus thurberi were damaged. Branch tips of Cereus thurberi at Gunsight Pass in western Pima County were frozen back 8 -16 inches and lateral branches less than 12 inches long were completely killed. In southern Sonora, leaves and branches of Ficus petiolaris, Randia echinocarpa and

Pithecellobium dulce were damaged. Leaves and branches of

Guazuma ulmifolia and flowers of Ipomaea arborescens were damaged in central Sonora. Source: Tumage and Hinckley, 1938;

Wiggins, 1937.

January, 1949. Minimum Temperature: 16 °F at University of

Arizona at Tucson, 17 °F at Tucson International Airport. Duration: 20 hours at Tucson International Airport. Observations of

236

Desert Plants 2(4) Winter 1980 -81

Damage to Plants: "This is the second coldest January that the state has experienced in its 55 years of climatic history ... A damaging freeze on the 4th, 5th and 6th resulted in heavy losses to fruits and vegetables in the southern part of the state. " Source:

U.S. Weather Bureau, 1949.

January, 1962. Minimum Temperature: 14 °F at Organ Pipe Cactus National Monument, 20°F at Tucson International Airport.

Duration: "Freezing temperatures continued after the first night through the next day and into the second night" on the south slope of the Santa Catalina Mountains between 2500 and 4500 feet. Observations of Damage to Plants: 35% to 75% of the individuals of Saguaro in various stands on the south slope of the

Catalinas were killed. Mortality in Barrel Cactus in the same area was also high. Damage was also reported to Cereus thurberi, C.

schottii, C. giganteus, Bursera microphylla and other cacti and sub - tropical shrubs at Organ Pipe Cactus National Monument.

Source: Niering et al., 1963; Lowe, 1964; Steenbergh and Lowe,

1976b.

January, 1971. Minimum Temperature: 11 °F at Campbell

Avenue Farm in Tucson, 20 °F at Tucson International Airport.

Duration: 18 hours at Tucson International Airport. Observvtions of Damage to Plants: High mortality of seedling and juvenile Saguaros was observed in Saguaro National Monument

East, and Cercidium microphyllum and Ferocactus wislizenii were killed. Die -back and complete kill of Olneya tesota was seen in the Tucson Mountains. At Organ Pipe Cactus National

Monument, both Cereus thurberi and C. schottii were damaged and "a substantial number of individuals" were killed. Near

Guaymas, Sonora Ficus palmera was injured. Both Ipomaea arborescens and Lysiloma watsoni suffered leaf and twig damage in the vicinity of Hermosillo, Sonora. Source: Steenbergh and Lowe,

1976a, 1977; Jones, 1979.

December, 1978. Minimum Temperature: 15 °F at Campbell

Avenue Farm in Tucson, 21 °F at Arizona- Sonora Desert Museum,

21 °F at Organ Pipe Cactus National Monument. Duration: 18 hours at Tucson International Airport. Observations of Damage to Plants: The following species were frozen to the ground at the

Arizona- Sonora Desert Museum: Hyptis emoryi, Tecoma stans,

Beloperone californica, Ambrosia ambrosioides, Bursera microphylla. At Organ Pipe Cactus National Monument Jatropha cinera,

J. cardiophylla, J. cuneata, Bursera microphylla and

Encelia farinosa were frozen to the ground. Olneya tesota,

Coursetia microphylla, Beloperone californica and Sapium biloculare were damaged. Encelia farinosa and Lysiloma watsoni were severely damaged in Palm Canyon near

Magdalena, Sonora. Bursera fragilis, Cereus thurberi and

Erythrina flabelliformis were also damaged. Source: Anonymous,

1979; Jones, 1979; personal observation.

Literature Cited

Anonymous. 1979. The severe freeze of 1978 -79 in the

Southwestern United States. Desert Plants 1: 37 -39.

Cooke, R. U. and R. W. Reeves. 1976. Arroyos and Environmental Change in the American Southwest.

Clarendon Press. Oxford.

Felger, R. S. and C. H. Lowe. 1967. Clinal variation in the surface -volume relationships of the columnar cactus

Lophocereus schottii in northwestern Mexico. Ecology

48: 530 -536.

Hastings, J. R. 1963. Historical Change in the Vegetation of a Desert Region. Ph.D. Dissertation. University of

Arizona. Tucson.

Hastings, J. R. and R. M. Turner. 1965. The Changing Mile.

University of Arizona Press. Tucson.

Jones, W. 1979. Effects of the 1978 freeze on native plants of Sonora, Mexico. Desert Plants 1:33 -36.

Leopold, L. B. 1951. Rainfall frequency: an aspect of climatic variation. Transact. Amer. Geophys. Union

32: 347 -35 7.

Lowe, C. H. 1964. Arizona's Natural Environment. University of Arizona Press. Tucson.

Niering, W. A., R. H. Whittaker and C. H. Lowe. 1963. The

Saguaro: a population in relation to environment.

Science 142: 15 -23.

Shreve, F. 1910. The rate of establishment of giant cactus.

Plant World 13: 235 -240.

Shreve, F.

1911. The influence of low temperatures on the distribution of the giant cactus. Plant World 14:

136 -146.

Shreve, F.

1912. Cold air drainage. Plant World 15:

110 -115.

Shreve, F.

1914. The role of winter temperatures in determining the distribution of plants. Amer. J. Bot.

1:

194 -202.

Steenbergh, W. F. and C. H. Lowe. 1976a. Ecology of the

Saguaro: I. The role of freezing weather in a warm desert population. pp. 49 -92, in Research in the Parks.

National Park Service Symp. Ser. 1. Government Print ing Office. Washington, D.C.

Steenbergh, W. F. and C. H. Lowe, 1976b. The Saguaro giant cactus: an ecological perspective. pp. 71 -78, in

Proceedings of the First Conference on Scientific Research in the National Parks. Vol. I. National Park Service Transactions and Proceedings Series No. 5.

Steenbergh, W. E. and C. H. Lowe. 1977. Ecology of the

Saguaro: II. Reproduction, Germination, Establishment and Survival of the Young Plant. National Park

Service Scientific Monograph Series No. 8. Government Printing Office. Washington, D.C.

Thornber, J. J. 1916. Introduction. pp. 119 -122, in J. C. T.

Uphof. Cold Resistance in Spineless Cacti. University of Arizona Agricultural Experiment Station Bulletin

No. 79.

Turnage, W. V. and A. K. Hinckley. 1938. Freezing weather in relation to plant distribution in the Sonoran Desert.

Ecol. Monogr. 8: 530 -550.

U.S. Weather Bureau. 1894 -1979. Climatological Data

Summaries, Arizona.

Wiggins, I. L. 1937. Effects of the January freeze upon the

Pitahaya in Arizona. Ca ct. & Succ. Soc. J. 8: 171.

237

Yatskievych

Ferns of Huachuca Mountains

Ferns and Fern Allies of the Garden Canyon

Area of the Huachuca

Mountains, Cochise

County, Arizona'

George Yatskievych

Department of Plant Sciences

University of Arizona

.

'The author wishes to thank Dr. Charles T. Mason, Jr. for much help and many suggestions during the course of this project.

Introduction

The Pteridophytes of southeastern Arizona are an interesting and diverse group of plants that have received little study in the recent past. Although several botanists have made collections in this area, beginning with J. G. Lemmon in the 1880s, there are few publications describing the Pteridophytes there, and most of these are outdated. The species are, however, all included in Morton's treatment of

Pteridophytes in Arizona Flora by Kearney and

Peebles (1960). Ferriss (1909) published a nontechnical article on fern species that might be found in

Cochise County. Goodding (1912) published a short article describing some species of ferns from the area. Phillips (1945, 1946) published some notes on Arizona ferns and (1946a, 1947) a checklist of

Arizona ferns. The Arizona Game and Fish Commission surveyed some of the plants, including

Pteridophytes, of the Fort Huachuca Military

Reservation in Cochise County, as part of a

Wildlife Area Investigation (1949 -1951). More recently, Reeves (1976) included the Pteridophytes in a flora of the Chiricahua National Monument.

The purpose of this present project was to survey the ferns and fern allies occurring in Garden

Canyon, a rich canyon area of the Huachuca Mountains in southeastern Arizona, to ascertain which species were growing there and to provide information on the habitats and distributions of these plants.

The Area

Garden Canyon and its tributaries are located on the northeastern side of the Huachuca Mountains, in Cochise County. The area has received little attention in the past 25 years because it is located on the Fort Huachuca Military Installation. It includes what J. G. Lemmon called Tanner Canyon, the source of many of his Huachuca Mountain collections.

Garden Canyon is an open canyon about 41/3 miles long that drains toward the northeast. The elevational change is from 5100 feet to 7750 feet. There are 3 major vegetation zones in the canyon. At the mouth is a desert -grassland zone, with scattered

Agave, Mesquite (Prosopis), Cholla (Opuntia) and

Prickly Pear (Opuntia) in a flat, dry, grassy area.

This quickly grades into an Oak/Manzanita zone that might best be termed a Chaparral. The zone is characterized by dense stands of mixed shrubs, predominantly Scrub Oak (Quercus) and Manzanita

(Arctostaphylos) with occasional cacti and larger

Juniperus. Finally, toward the upper end of the canyon, there is a gradual transition to a conifer forest, with Pinus and Douglas Fir (Pseudotsuga)

238

Desert Plants 2(4) Winter 1980 -81 the dominant vegetation. This zone occurs as low as 5900 feet. A stream that is intermittent with perennial flow in some areas is found throughout the canyon bottom.

The study area also included the 3 primary tributary canyons of Garden Canyon. The uppermost of these is Sawmill Canyon, which branches toward the southeast near the upper end of Garden Canyon.

This tributary canyon is about 21/4 miles long, with an elevational change from 5900 feet to well over

7750 feet. It is characterized by many open, barren outcroppings of dolomitic limestone, on which few plants grow. The predominant vegetation zone is the conifer forest but there are many scattered patches of Chaparral. A perennial spring is located about 3/4 mile from the canyon mouth.

Also in the upper half of Garden Canyon, is

Scheelite Canyon, which branches toward the southeast and is about 21/4 miles long. Its elevation is

5800 -7250 feet, with a box at the upper end. This narrow, rocky canyon is walled by high cliffs, making it a very sheltered habitat. An intermittent stream runs in the canyon bottom. The third major tributary of Garden Canyon is McClure Canyon, which branches toward the northwest at 5500 feet.

This tributary is about 21/2 miles long and climbs to the ridge at 6750 feet. It is one of the wettest areas in the Huachuca Mountains, with a large series of perennial springs and a perennial stream in the upper half. The rest of the canyon is dry Chaparral, however.

The Garden Canyon area is rich in Pteridophytes because it contains many different exposures in a variety of habitats. Of particular importance are the smaller isolated habitats that are scattered through the canyon system. These account for the limited distributions of some species as well as the

Pteridophyte diversity. One of the commonest isolated habitats is that of the limestone cliff which occurs below the ridge in several areas throughout the canyon system. The limestone substrate seems to allow good seepage and the craggy nature offers both good protection and good anchorage for the plants. Greater numbers of plants were found on cliffs with a northern exposure than on comparable sites with other exposures.

Another common smaller habitat is that of the steep and very dry rocky hillside. This occurs in a few locations in Garden Canyon and lower McClure

Canyon. The most xerophytic of the Pteridophytes of the study area grow in this exposed habitat. Such plants are usually dormant, with brown, curled, dry fronds during the drier portions of the year.

The Pteridophytes are generally found growing from under the larger rocks; they seldom grow in open soil.

A third major isolated habitat is that of the riparian zone which occurs in the canyon bottoms throughout the Garden Canyon area. It is restricted to the areas immediately bordering the streams, except in upper McClure Canyon where there are large riparian groves. The dominant riparian vegetation is Cottonwood (Populus), Sycamore (Platanus),

Walnut (juglans) and Maple (Acer), with a dense, varied understory. The Pteridophytes that occur in this habitat are confined to the areas where the stream flow is perennial. They are becoming more widely distributed as the water re- routing by the

U.S. Army brings more water to the surface.

Methods

For this study, the Garden Canyon area was roughly divided into 15 sections. Each section was examined several times. The bulk of the field work was accomplished from January to July of 1978, with periodic trips afterward to verify some of the findings. Each section was thoroughly searched and all likely habitats for Pteridophytes were examined.

The survey area extended from the canyon bottom to the nearest ridge on each side and included all tributaries and ravines. The only exception to this procedure was in upper Sawmill Canyon, where the survey ended at the Fort Huachuca boundary fence, about 100 feet (in elevation) below the ridge.

Collections were made of each species found.

Voucher specimens were deposited at the University of Arizona Herbarium (ARIZ) and at the field herbarium of the Fort Huachuca Game Management

Office. Specimens were identified using Arizona

Flora by Kearney and Peebles (1960), and where necessary the names were brought up to date.

Specimens were examined at the University of

Arizona Herbarium, particularly the numerous

Huachuca Mountain collections of Goodding, in order to pinpoint the locations of some of the less common species in the canyon system.

Results

During the course of the survey 33 different

Pteridophytes were collected, comprising 13 genera and 32 species. One additional species was found during the herbarium search, which could not be located in the field. The genera and species in the

Cheilanthes fendleri.

Notholaena sinuata.

240

Desert Plants 2(4) Winter 1980 -81 following list have been alphabetized to facilitate species location.

SELAGINELLACEAE

Selaginella underwoodii Hieron var. dolichotricha

Weatherby. Found at only one location in the study area, but locally common there. This spikemoss grows at 6700 feet, on rock faces at the upper end of a steep ravine, located at the head of a small side canyon that branches southward near the mouth of Garden Canyon. This ravine was found to be especially rich in Pteridophyte diversity, harboring 6 species of ferns and fern allies uncommon in the Garden Canyon system. The ravine is moist with seepage year -round and is relatively sheltered by the surrounding cliffs. The substrate is mainly limestone, with several large granitic outcroppings. The topography is such that a series of ledges is formed in the middle.

EQUISETACEAE

Equisetum hiemale L. var. affine (Engelm.) A. A. Eaton.

Found growing semi -aquatically in sandy soil in riparian areas where the stream flow is perennial. This species occurs throughout Garden Canyon, above 5400 feet, in scattered colonies. A large stand is also located in a marshy area, in mucky soil, at McClure Springs.

Equisetum laevigatum A. Braun. Collected at the same locations in Garden Canyon as the previous species, but absent in McClure Canyon. Where the 2 species grow together, this is invariably the more abundant one. It also seems to form more extensive colonies than E. hiemale, with the plants growing further from the surface of the water. The hybrid between E. hiemale and E. laevigatum

(E. Xferrissii Clute), common elsewhere in southern

Arizona, was not found in the Garden Canyon system.

POLYPODIACEAE

Adiantum capillus- veneris L. Limited to one location in the Garden Canyon area. This species was found only in the vicinity of McClure Springs, at 6250 feet. It grows on elevated stream banks below the springs and on moist cliff overhangs, in mucky soil. It is also confined to relatively shady locations. The fronds seem to die back every winter.

Asplenium exiguum Bedd. Included in the survey on the basis of a single specimen (Goodding 142 -52, ARIZ). The label on this sheet reads "Steep side canyon; Garden

Canyon, Huachuca Mountains." The collection date is

December 26, 1952. No plants of this species were seen in the Garden Canyon system during this survey.

Asplenium monanthes L. Uncommon in the study area.

A few plants were found in a very sheltered rock crevice, with mosses, at 6600 feet in the same ravine described earlier for Selaginella underwoodii.

Asplenium resiliens Kunze. Collected in moist areas, in and around Scheelite Canyon, between 5800 and 7000 feet. This species grows from cracks in rocks and on limestone cliff faces, near streams and seepage areas. It is fairly common in protected areas of the Scheelite Canyon stream bed, but its range does not extend to the box at the head of the canyon, probably because the wet areas become more localized and less permanent as the canyon widens into the box.

Boomeria hispida (Mett.) Underw. One of the commoner ferns in the Garden Canyon area, below 6000 feet.

It is abundant under shrubs in the Chaparral habitat, but may also be found on partially shaded rock ledges.

Cheilanthes alabamensis (Buckl.) Kunze. Restricted to moist, rocky situations. A small colony of this fern was found near the mouth of Scheelite Canyon, at the 6000 foot level, where it was growing in the canyon bottom with Asplenium resiliens.

Cheilanthes eatoni Baker. A common fern of rocky situations, throughout the Garden Canyon area. It grows abundantly in moister situations, and is replaced on the driest, most exposed cliffs by Cheilanthes lindheimeri.

Forma castanea (Maxon) Correll is much more abundant than f. eatoni, which grows in scattered locations, throughout the range.

Cheilanthes feei Moore. Widely distributed in the survey area, but nowhere abundant. This fern is restricted to the limestone cliff habitat, growing from cracks in the cliffs, and is less common in exposed situations.

Cheilanthes fendleri Hook. Abundant in the Chaparral habitat, often growing with Boomeria hispida and

Cheilanthes wootoni. It grows from under rocks, and in rocky soil, often shaded by trees and shrubs.

Cheilanthes lendigera (Cay.) Swartz. Restricted to a single location in the survey area. A colony of this species was found growing at the 6500 foot level in the same steep ravine described earlier for Selaginella underwoodii and

Asplenium monanthes. It was locally common there.

Cheilanthes lindheimeri Hook. Found in several habitats, throughout the survey area. It grows in large patches in the Chaparral habitat, and from exposed cliff faces. It is one of the most xerophytic of the area

Pteridophytes, and may even be found growing from under rocks on the exposed, dry, rocky hillsides.

Cheilanthes villosa Davenp. Uncommon in the Garden

Canyon area. This species was found on a south -facing, dry, steep, rocky hillside, at 5900 feet, across from the mouth of Scheelite Canyon, in Garden Canyon. It also occurs in this habitat below 6000 feet at a few other locations in Garden Canyon.

Cheilanthes wootoni Maxon. Abundant in the Chaparral habitat, usually growing with Boomeria hispida and

Cheilanthes fendleri.

Cheilanthes wrightii Hook. Restricted to one locality in the survey area. A small colony of this species was found growing on a rocky slope near the canyon bottom, in lower Garden Canyon, at 5300 feet. The fronds of this small xerophyte dry up and become inconspicuous fairly early in the year and it is possible that the species is more widely distributed in the survey area than the collections indicate.

Cyrtomium auriculatum ( Underw.) Morton. _

"Phanerophlebia auriculata Underw." Restricted to a

Yatskievych Ferns of Huachuca Mountains

241 single location in the survey area. A colony of this species was found at the same location earlier described for

Selaginella underwoodii. The plants grow in moist soil with the rhizomes deeply recessed at the base of an overhanging terrace.

Cystopteris fragilis (L.) Bernh. var. tenuifolia (Clute)

Brown. Abundant in Sawmill Canyon, above 7200 feet.

This species grows in moist, loamy soil, under conifers.

The deciduous fronds do not appear until late May.

Notholaena aschenborniana Klotzsch. Restricted to one locality in the survey area. A colony of this species was found on the south -facing, dry, steep, rocky hillside in

Garden Canyon, across from the mouth of Scheelite

Canyon, between 5800 and 5900 feet. Some of the plants were growing with Cheilanthes villosa.

Notholaena aurea (Poir.) Desv. Found at the mouth of

Garden Canyon, under trees and shrubs near the edge of the Chaparral zone. This species inhabits the opener sections of the Oak/Manzanita habitat and was also found on an open hillside in middle McClure Canyon. It grows below the 6000 foot level.

Notholaena cochisensis Goodding. A common inhabitant of the steep, dry, rocky, exposed hillsides, throughout the Garden Canyon area.

Notholaena grayi Davenp. Restricted to steep, dry, rocky, exposed hillsides below 5700 feet. This species was found in both lower Garden Canyon and lower McClure

Canyon.

Notholaena integerrima Hook. Uncommon on steep, dry, rocky, exposed hillsides throughout Garden Canyon.

This species is much less common than related species

N. sinuata and N. cochisensis and is less widely distributed. It is more frequent in the upper half of Garden

Canyon than the lower half, but is nowhere abundant.

Notholaena limitanea Maxon var. limitanea. Found throughout the Garden Canyon area, but nowhere abundant. This species is found in moist situations, growing from under rocks or from cracks in cliff faces. It is most common in shady areas, adjoining the riparian zone.

Notholaena sinuata (Lag.) Kaulf. A common inhabitant of the steep, dry, rocky, exposed hillsides, throughout the

Garden Canyon area.

Pellaea atropurpurea (L.) Link. Frequent in moist, rocky situations, throughout the survey area. This species is frequently found growing with Notholaena limitanea, but is more abundant.

Pellaea intermedia Mett. Found on steep, dry, exposed, rocky hillsides and cliffs below 6500 feet, in Garden

Canyon and McClure Canyon. This species is not very abundant in the survey area.

Pellaea ternifolia (Cay.) Link var. wrightiana (Hook.) A.

F. Tryon. = " Pellaea wrightiana" Hook. Abundant throughout the survey area. This species was found in every habitat in the Garden Canyon area, except on the most exposed cliffs. It was less common in very moist, riparian situations. The individual plants were widely scattered.

Pityrogramma triangularis ( Kaulf.) Maxon var. maxonii

Weatherby. Restricted to one location in the survey area.

This species was found in a dense colony in the micro habitat created by the sheltering over -hang of a large boulder, just below the ravine described earlier for Selaginella underwoodii and Asplenium monanthes. The pocket was densely shaded and the plants were growing in very moist, fine, sticky soil. This is the first published report of

Pityrogramma triangularis var. maxonii from Cochise

County, although this population was previously collected from by Goodding (163 -50, 139 -52, 11 -53) in

1950 -1953.

Polypodium thyssanolepis Klotzsch. Restricted to very sheltered, moist situations. This species was found in two locations in the survey area, growing in overhanging limestone cliff areas. The first was in the ravine previously discussed for Cheilanthes lendigera and Selaginella underwoodii. The second was in a short series of cliffs just above the canyon bottom, in lower Garden Canyon, in the r4parian zone, at 5300 feet.

Woodsia mexicana Fee. Widely distributed in Garden

Canyon, below 6500 feet. This species occurs in moist, rocky areas, and on moist limestone cliffs. It is able to grow in fairly exposed situations, and the deciduous fronds appear as early as March.

Woodsia plummerae Lemmon. Widely distributed between 5300 and 7750 feet in Garden and Sawmill

Canyons. This plant is found in the habitat previously described for Woodsia mexicana, as well as growing with Cystopteris fragilis, in moist soil under trees in the confier forest. It also has deciduous fronds that appear as early as March.

Literature Cited

Arizona Game and Fish Commission, Wildlife Restoration Division. 1949 -1951. Fort Huachuca Wildlife Area

Investigations -Job Completion Reports of the

Charles T. Vorhies Game Habitat Research Project.

pp. 1 -28.

Ferriss, J. H. 1909. Ferns of Cochise County, Arizona. Fern

Bull. 17: 1 -7.

Goodding, L. N. 1912. New Southwestern ferns. Muhlenbergia 8: 92 -94.

Kearney, T. H., R. H. Peebles and Collaborators. 1960.

Arizona Flora. 2nd ed. University of California Press.

Berkeley. pp. 27 -49.

Phillips. W. S. 1945. Some notes on Arizona ferns. Amer.

Fern Journ. 35: 58 -60.

Phillips, W. S. 1946. Additional notes on Arizona ferns.

Amer. Fern bourn. 36: 58 -60.

Phillips, W. S. 1946a. A checklist of the ferns of Arizona.

Amer. Fern bourn. 36: 97 -108.

Phillips, W. S. 1947. A checklist of the ferns of Arizona, cont. Amer. Fern bourn. 37:13 -20, 39 -51.

Reeves, T. 1976. Vegetation and Flora of Chiricahua National Monument, Cochise County, Arizona. MS thesis. Arizona State University. Tempe. pp. 99 -102.

Cheilanthes lindheimeri.

Cheilanthes eatoni.

Ya tskievych Ferns of Huachuca Mountains

243

Notholaena limitanea (upper) with Cheilanthes lindheimeri.

244 Desert Plants 2(4)

Winter 1980 -81

Reviews

"

Plants of Deep Canyon and the

Central Coachella Valley, California

Jan G. Zabriskie. Drawings by Carol Lewis. Philip L. Boyd

Deep Canyon Desert Research Center, University of

California, Riverside. 1979. 175 pp.

The author intended the book not only for scientists interested in desert research, but also "the expanding audience of people interested in native desert plants as they occur in their natural environment."

A habitat map in color folds out at page 13, followed by a series of nine chapters, each presenting a sketch of the vegetation of one of the habitats. Rather than presenting a standard floristic list, the author has reported the species in tabular form, graphing the elevational range of each.

This has an obvious visual advantage or graphic impact which allows the elevational ranges of different species to be more easily compared. It has the disadvantage, however, of leaving no room for helpful annotations and species discussions. Such information is presumably reported in the chapters dealing with vegetation by habitat.

This would probably be disconcerting only to a traditional plant taxonomist accustomed to scanning through annotated taxonomic treatments for observations on a certain family or genus being researched. Noteworthy observations scattered through the text can presumably be located by using the index.

A final chapter presents ecological data (principally percent cover and species diversity) from surveys made at

122 -meter elevational intervals along a transect. Charts are presented which compare percent cover of specialized plant life forms to total plant cover in major habitats. Percent evergreen cover relative to total plant cover appears to be bimodal, being particularly low between 488 and 732 meters on rocky slopes. Presumably these sites had little of the Creosotebush (Larrea tridentata) of lower elevations and little of the Pinyon (Pinus monophylla) and

Chaparral vegetation of slightly higher elevations.

Another bimodal distribution appears in the chart which displays percent winter -deciduous cover relative to total plant cover. This bimodality must come from the phenomenon of cold air drainage at the intermediate elevations, cold -tolerant Mesquite (Prosopis glandulosa var.

torreyana) being present on the valley floor and other cold -tolerant winter -deciduous species on the high montane slopes.

Percent succulent cover relative to total plant cover is high in just those elevations where winter -deciduous cover is low, again suggesting a response to cold air drainage. On rocky slopes at 732 meters elevation, succulents provide over 40% of the plant cover. Percent drought

deciduous cover relative to total plant cover, clearly an indicator of aridity, is virtually nil on the valley floor, suggesting the presence of water, high from 122 to 1,100 meters, and very low or zero at higher elevations, in classical test -book fashion.

Dry Lands: Man and Plants.

Robert Adams, Marina Adams, Alan Willens and Ann

Willens. The Architectural Press Ltd. London, England.

1978. vii + 152 pp. Price, 15.00 British Pounds.

On thumbing through this book it appears to be a scholarly review. Upon closer examination, the book attempts to cover so many topics in so small a space that it falls into the bad habit of oversimplifying. Under "DESERT VEGE-

TATION TYPES" it recognizes 1) ephemeral plants, 2) succulent perennial plants, and 3) woody perennial plants, said to be mutually exclusive categories. But nothing is said of the herbaceous (i.e. nonwoody) perennials or the annuals which are not ephemeral or only facultatively so.

Succulent perennials are said to be either spiny like the

Cactaceae or "non -spiny but physiologically swollen plants." For a plant scientist to conjure up an image of a

"physiologically swollen plant" he must imagine some pathological condition resulting from a plant being thrust into some powerful solution of unbelievable osmotic concentration. The first part of the statement concerning the spiny or non -spiny nature of succulents is like saying that a plant either has stiff branches, or if it doesn't, then it has green leaves. Of what relevance, you ask the author. Such statements disincline a botanist to spend much time in seriously reading the book. In the same paragraph, the ability of succculents to close their stomata in the daytime and open them at night is said to be a phenomenon which "is being intensively researched, especially in the

U.S.A." And here in Arizona, we thought that this had been thoroughly reported on by scientists at Tumamoc

Hill in Tucson well over 50 years ago.

Important Notices

Subscriptions to Desert Plants

To obtain a one -year subscription to

Desert Plants, just send $10 to the address below

Desert Plants

Boyce Thompson SW Arboretum

P.O. Box AB

Superior, Arizona 85273

Make sure you provide your current address with zip code. If the subscription is a renewal, please say so to avoid receiving two copies of the same issue.

In the case of gift subscriptions, we will send a letter to the recipient telling who is sending the gift, if this is requested. Of course, no extra charge.

M AVA!t7M^ 3h.VtIämartt:sP'.

Fifth Annual Arboretum Plant Sale

Dates

April4 -5, 1981

(Saturday and Sunday)

Location

Boyce Thompson Southwestern Arboretum

U.S. Highway 60, 3 miles west of Superior,

Arizona

(60 miles east of Phoenix; 100 miles north of Tucson)

Remember

We recommend that you attend the plant sales that our sister institutions have as well.

March 28 -29, 1981

Plant Sale at Désert Botanical Garden,

Phoenix

April 11 -12, 1981

Plant Sale at Arizona -Sonora Desert

Museum, near Tucson

245

Jimson Weed, Tolguacha, or Thorn Apple (Datura meteloides) photographed at the old Silver King Mine near the Arboretum by Leslie Ely.

The Story of Jimson Weed. Species of Datura grow on sites which are open, disturbed, sunny and often arid.

Cowboys, desert dwellers or denizens of "waste places" often refer to the plants by the name Jimson Weed. This is in reality a contraction for "Jamestown Weed" (Datura stramonium), a plant which became infamous in colonial

Virginia. In 1870 J.

E. Dodge reported that "Datura meteloides grows abundantly in Arizona" and that "the

Mohave Indians gather the leaves and roots, bruise and mix them with water." After being allowed to stand for several hours, "the liquid is drawn off. It is a highly narcotic drink, producing a stupefying effect." The California

Indians "use a decoction of this species to stimulate young females in dancing." The Pah -Utes "... ferment in the sun a watery infusion of the bruised seeds, and drink the liquor for the purpose of intoxication." Pharmacologists Edward

P. Claus and Vano E. Tyler discussed D. stramonium in

1965, recording that early settlers near Jamestown in colonial Virginia "used it as a 'pot herb' with fatal results."

Charles F. Millspaugh in 1892 characterized the Jamestown plant as growing in waste places or garbage heaps and noted that "... the American Aborigines named it The

White Man's Plant ..." in allusion to its place of growth "... near the homes of the civilized." In 1922 L. H.

Bailey wrote that at the "first successful settlement in

America- Jamestown, Virginia, 1607 ..." the men ate

Datura "... with curious results. Capt. John Smith's account of their mad antics is very entertaining." The colonial historian Beverly (in History of Virginia, p. 121) recorded that soldiers sent to put down Bacon's Rebellion gathered the young sprouts and ate them as a pot herb,

"the effect of which was a very pleasant comedy, for they turned natural fools upon it for several days. One would blow up a feather in the air; another would dart straws at it with fury; another, stark naked, was sitting up in a corner like a monkey, grinning and making maws at them; a fourth would fondly kiss and paw his companions."

After eleven days they "... returned to themselves again, not remembering anything that had passed." Unfortunately many other records of Datura- eating list death as the end result. For example, in 1911 L. H. Pammell recorded a case where some boys "... imagined themselves Indians and roamed about and ate parts of various plants ..." including

Jimson Weed. "One died in a state of wild delirium; another was saved after heroic treatment ..." Pammell also recorded the poisoning of five children who had eaten

Datura growing in a garden "under the fanciful trade name of Night- blooming Cactus." Daturas have become spread as weeds throughout much of the world and several authors have stated that "Thugs" and "Assassins" in

India poisoned people with them in furtherance of their criminal activity.

Volume 2. Number

4. Winter 1980 -81.

Desert

Published by The University of Arizona for the

Boyce Thompson Southwestern Arboretum

Plants

Editorial- Fitness and Flexibility in Relation to Selection and

Propagation of Desert Plants

204

Propagation Techniques for

Desert Plants

205 a minisymposium

Arboretum Progress

217

Robert T. McKittrick

Special Supplement- Living With

Desert Plants Through the Year

219

Sources of Arid Land

Plant Seeds

231

Kent C. Newland

Catastrophic Freezes in the Sonoran Desert

232

Janice E. Bowers

Ferns and Fern Allies of the Garden

Canyon Area of the Huachuca Mountains,

Cochise County, Arizona 237

George Yatskievych

Reviews 244

Fifth Annual Arboretum Plant Sale

245

The Story of Jimson Weed 246

The red -flowered hummingbird -pollinated Silver -Torch Cactus

(Cleistocactus tupizensis) of Argentina growing at the Boyce

Thompson Southwestern Arboretum. When propagated from cuttings of mature plants, flowers appear the first year on the side which had faced the sun. See article on page 205.

204 Desert Plants 2(4)

Winter 1980 -81

Desert Plants

A quarterly journal devoted to broadening knowledge of plants indigenous or adaptable to arid and sub -arid regions, to studying the growth thereof and to encouraging an appreciation of these as valued components of the landscape. Subscription price is $10.00 per year.

Frank S. Crosswhite, editor

Published by The University of Arizona for the Boyce Thompson Southwestern Arboretum

The Boyce Thompson Southwestern Arboretum at

Superior, Arizona, is cooperatively managed by The

Arizona State Parks Board, The Boyce Thompson Southwestern Arboretum, Inc., and The University of Arizona.

Editorial

Fitness and Flexibility in Relation to Selection and

Propagation of Desert Plants. -Population geneticists refer to fitness as the degree to which a population passes on its specialized adaptive heredity unchanged to the next generation. Populations display a type of meristic variation with regard to adaptive characteristics, -a variation which often when graphed produces a "normal curve" with an adaptive peak flanked by less adaptive sides. In any desert situation where rigorous growing conditions change little from year to year, plant populations can be expected to exhibit a high degree of fitness. The rigorous environment tends to truncate the curve fore and aft since the rigor -surviving progeny which live to reproduce are those which fall closest to the adaptive peak.

But although plants must have a high degree of fitness for the present environment, their populations must also exhibit a degree of flexibility to cope with changes in that environment. There is an ever -increasing body of evidence suggesting that climate and growing conditions have indeed significantly changed even in historic times in many of the world's deserts. Generally, as fitness increases, flexibility decreases and vice versa. As a result, each population must strike a balance between fitness and flexibility.

For the short term, a plant population must be fit for the present environment. But for the long term it must be flexible to meet new rigors of some unknown future situation.

Through selection and propagation man is now exploiting the fitness- flexibility balance for his own advantage.

Propagation of plants by man itself implies selection. Man is selecting the plants which will reproduce. Of the hundreds and thousands of plants which are adapted to function and survive under desert conditions, man has selected a small percentage to propagate and use for his purposes.

The fitness of these plants for desert conditions is truly a gift of nature. Plant breeders take the built -in flexibility, often enhance it with hybridization, and select plants with characteristics superior for utilization by man.

Mankind is now becoming the one overpowering agent of change in desert environments. Plant populations with flexibility sufficient to enable them to become commensal with man will survive where man's populations expand in the deserts. Others may pass from threatened and endangered lists to extinction. The Boyce Thompson

Southwestern Arboretum is already a "Noah's Ark" of sorts for a number of desert plants which are either extinct in nature or nearly so.

When man propagates by seed, when a garden situation removes some of the rigors of the environment, or when

"volunteer" plants are of suspected hybrid origin, man commonly rogues through the variable progeny to select types which suit his fancy. In this manner a large number of garden forms of desert plants have been selected over the years, many of which are totally unknown in nature.

Many of these are perpetuated by man for his use through vegetative propagation. This latter process has had a rebirth of interest recently under the name "cloning."

Every plant produced by such a process is identical to the mother plant.

Man in desert areas has the capability of modifying his environment by drawing on the flexibility of natural plant populations, selecting for fitness to meet his own very specific needs, and if necessary perpetuating by clonal propagation. But preservation of entire native desert plant populations having a balance of fitness and flexibility is desirable if for no other reason than to assure an adequate range of germplasm for the future. Just as it would be impossible to preserve all of the brilliance, creativity, genius and genetic potential of the human species by saving only one female and one male for propagation purposes, so too is there a need to preserve a wide range of germplasm of each potentially useful desert plant species.

Insofar as Russian Thistle (Salsola kali) has recently been shown to be useful, perhaps no desert plant should be allowed to become extinct in nature.

Propagation

Techniques for

Desert Plants

Part I of a minisymposium with contributions from

Kent C. Newland

Boyce Thompson Southwestern Arboretum

Sarah Ives

V &P Nurseries, Inc.

Gene E. Joseph and Mark A. Dimmitt

Arizona -Sonora Desert Museum

Marc Mittleman

Desert Botanical Garden

R. E. Foster

Department of Plant Sciences,

University of Arizona

Carol Scannell

Tanque Verde Greenhouses

Department of Plant Sciences Faculty

University of Arizona

W. R. Feldman

Department of Plant Sciences,

University of Arizona

Frank S. Crosswhite

Boyce Thompson Southwestern Arboretum

Chuck Hansen

Arid Land Plants

Minisymposium

Propagation Techniques 205

Recently the journal Desert Plants contacted a number of growers, both commercial and governmental, to see if enough interest existed to assemble a miniature journal symposium dealing with propagation techniques. A large number of persons with expertise in the field shared their knowledge through both written communication and oral discussion. The response was so large and enthusiastic that it seemed desirable to publish a sample of the contributions immediately as Part I and to continue the minisymposium in a future issue.

Under the term plant propagation we ordinarily include any technique by which mankind intentionally increases the number of individuals of a plant. On the other hand, the term plant reproduction is ordinarily used to refer to the natural increase in numbers of individuals. Many times man chooses to propagate a plant by taking advantage of natural reproductive mechanics inherent within the species. Although such propagation is quite common in animal breeding (i.e. bringing two animals together to mate), it is less commonly practiced in propagating plants.

Successful plant growers customarily hire horticulturists adept and knowledgeable at artificial propagation techniques to produce seedlings, rooted cuttings or grafted material which will then be "grown on" to larger size.

Within a company or governmental agency the person with the title "Plant Propagator" is typically greatly respected and may even be held in awe. This person holds the success of the enterprise in his or her hands. The propagator is knowledgable concerning theory, knows a good number of "trade secrets," has a green thumb, and may occasionally be accused of practicing black magic.

Although there may be a number of alternative procedures which would at first thought be capable of yielding similar results, one specific technique may actually prove to be greatly superior. For example, a hard impervious seed coat may be breached by scarifying with a file or sandpaper or grinding wheel, by treating with hot water, by soaking in concentrated sulfuric acid, or by other techniques.

However, the treatment in sulfuric acid has the added advantage of cleansing the seed of any pulp or other material which might be present and of killing fungi and bacteria. Nevertheless, acid treatment may not give as good a result as a hot water soak, depending on the plant.

Seeds are by nature dormant structures. The embryonic plant is already present as well as a food reserve for the early stages of growth. When dormancy is broken and moisture gains entrance into the seed, dehydrated energy in the form of adenosine triphosphate (ATP) goes into solution and triggers rapid changes. Much of the time of the propagator is often devoted to discovering methods of artificially breaking dormancy and causing the ATP to become active. Techniques may be as different as the species are one to the other.

Vegetative reproduction (not involving seed germination) is a time- honored method of quickly obtaining duplicate material identical to the original. There are a great number of procedures varying from tissue culture to rooting cuttings under intermittent mist. Many types of succulent plants, particularly, are propagated vegetatively and there is a wide divergence in methods depending on the species in question.

The Ruby Ball Cactus, a somatic mutant of

Gymnocalycium mihanovichii var. frederickii, provides an excellent example of a plant which must be perpetuated by vegetative means (= cloning). It is propagated by grafting offsets onto a chlorophyll- bearing understock.

This minisymposium brings together a number of previously unpublished findings. It does not take the place of textbooks on the subject and does not purport to be corn plete or encyclopedic. Books previously published which are quite useful are listed below.

References

Brooklyn Botanic Garden. 1957. Handbook on Propagation. Plants and Gardens Vol. 13, No. 2. Special Issue.

Copeland, L. O. 1976. Principles of Seed Science and

Technology. Burgess Publishing Co. Minneapolis,

Minn.

Everett, Percy. 1957. A Summary of the Culture of

California Plants at the Rancho Santa Ana Botanic

Garden, 1927 -1950. Rancho Santa Ana Botanic Garden. Claremont, Calif.

Hartmann, Hudson T. and D. E. Kester. 1968. Plant Propagation, Principles and Practice. Prentice Hall.

Englewood Cliffs, N.J.

Reilly, Ann. 1978. Park's Success With Seeds. Geo. W.

Park Seed Co., Inc. Greenwood, South Carolina.

Schopmeyer, C. S. (ed.) 1974. Seeds of Woody Plants in the

United States. U.S.D.A. Handbook 450.

U.S. Department of Agriculture. 1948. Woody Plant Seed

Manual. U.S.D.A. Misc. Publ. 654.

Wells, James S. 1955. Plant Propagation Practices. Mac-

Millan Publishing Co., Inc. New York.

Wright, R. C. M. 1973. The Complete Handbook of Plant

Propagation. MacMillan Publishing Co., Inc. New

York.

The Baggie© Method of Cactus and Succulent Seed

Germination (Information courtesy of Kent C. Newland,

Boyce Thompson Southwestern Arboretum). Fill 23/a "wide square plastic pots with growing medium of '/3 commercial potting soil, 1/3 coarse sand and 1/3 pumice or perlite. Drench the soil with a solution of Captan® fungicide in distilled water to prevent damping off of the young seedlings. Sow seed in the pots, labelling each with name of the plant, date of sowing and source. Enclose each pot in a plastic Baggie® with a twist tie. This technique simulates greenhouse conditions of high humidity for maximum germination. Shading the pots also seems to benefit germination by simulating low light conditions as found in rock cracks where young cactus and succulent seedlings have been noted.

The seeds will germinate in about two weeks. After the seedlings have made two months of growth, the baggie can be removed. Continue to water. After four or five months the seedlings can be transplanted individually to 2" -wide

Pincushion Cacti of the genus Mammillaria have become popular as flowering greenhouse ornamentals in

Germany, the Netherlands, England, Japan, and elsewhere because they are propagated so readily from seed sent from Mexico and the Southwestern United

States where they are native.

pots and fertilized with Miracle Gro ° The recommended sowing time for cacti is spring, for summer -growing succulents (Euphorbia, Cissus, Adenium) also spring, for winter -growing suc culents (Aloe, Mes embryanthaceae,

Crassulaceae) fall.

Growing Boojum Trees From Seed (Information courtesy of Sarah Ives, V & P Nurseries, Inc., Mesa, Arizona).

To germinate Idria columnaris, collect fresh seed and begin the germination process in May when the older plants are beginning to become dormant. This allows the seedlings to attain a size and vigor sufficient to cope with the May through October dormancy period of the next year. Prepare a soil mix of 1/3 sand, 1/3 peat and 1/3 perlite.

Place this into small seed flats or directly into 21 /a "diameter deep rose pots. Wet the soil and allow to drain.

Use of a fungicide at this stage is optional. If moisture is dispensed to the developing seedlings properly the fungicide will not be needed and if the moisture conditions are not maintained properly the plants will die when the fungicide is leached away anyway.

Place the seed on the damp soil and cover with a layer of soil as thick as the seed. Although the flats or pots can be covered with plastic to keep the soil moist, this is not necessary and may in fact keep the soil too soggy. The seeds germinate within 24 hours and need good ventilation. As the seedlings grow they should be lightly watered but the soil surface should be allowed to dry out.

If the seedlings were started in a flat, once they become somewhat woody they can be separated and planted in individual 23/4"- diameter deep rose pots. During the May to October dormancy period watering should be greatly reduced. This is the most critical period when young seedlings in nature are apt to die. By carefully monitoring the moistness of the soil and by providing optimum greenhouse conditions, a high percentage of the plants will survive this critical period of the first year.

During dormancy the seedlings lose their leaves. Those plants which remain hard and firm will leaf out in the fall but any which become soft and wrinkled should be disposed of.

When the young plants are leafy and growing they can be watered frequently as long as the soil is allowed to dry out between waterings. Use of a fertilizer such as Miracle

Gro° at 1/3 the strength recommended for house -plants can be used every third or fourth watering. The plants thrive on hard greenhouse light and good ventilation.

Home gardeners living where temperatures do not often go below 26 °F should transplant seedlings into the soil when about one year old after they have leafed out from the first dormancy. Screening to protect from rabbits and

208 Desert Plants 2(4)

Winter 1980 -81

Young seedlings of cacti have large fleshy cotyledons under the short plump spiny plant body.

Seedling of Boojum Tree (Idria columnaris).

rodents may be necessary for three to five years. In coastal areas or other regions where fog, humidity and clouds temper the intensity of the sun, plants may be placed in

80% to nearly total sun. In areas with high intensities of light and heat, such as southern Arizona, filtered shade is necessary for young seedlings. When grown at home as a container plant, good filtered light of a patio should prove successful. If the plant must be grown indoors without a greenhouse, a position on the sunniest window -sill should be chosen.

Propagation of Certain Semi -succulent Shrubs of the

Sonoran Desert (Information courtesy of Gene E. Joseph and Mark A. Dimmitt, Arizona -Sonora Desert Museum).

Discussed below are procedures used for propagating the species of Bursera, Fouquieria and Jatropha. BURSERA

SPP.: Burseras are easy to grow once they get past the early seedling stage. Problems are low seed viability and susceptibility of seedlings to fungus until the stems begin to harden a few weeks after germination. Plants grow rapidly if generously potted, but growth slows greatly as soon as the roots become potbound.

Seeds of Bursera laxiflora were collected from cultivated plants at the Arizona- Sonora Desert Museum. Seeds of three other species were collected in Baja California Sur in August of 1979. Seeds were sown in a greenhouse in 1:1 perlite:vermiculite on May 9, 1980. Germination was complete in less than two weeks. Approximate germination was 40% for B. laxiflora, 30% for B. hindsiana, 15% for B. microphylla and less than 5% for B. odorata.

Examination of samples of the same seed collections revealed that most of the seeds were hollow. We surmise that most of the viable seeds germinated. A second collection of B. microphylla sown a few weeks later resulted in about 50% germination. Among seeds collected on the same day from the same plant, darker seeds had higher germination.

During their six weeks in the seed flats the seedlings were treated four times with Banrot° or [email protected] fungicides and fertilized once with full- strength 20- 20 -20.

About 30% of the seedlings succumbed to fungal diseases.

At six weeks the plants were transplanted into 21/4"diameter rose pots, with mortality negligible afterward.

They were treated approximately weekly with Captan

[email protected] or Terrachlor° and fertilized bimonthly for the next seven weeks. In their fourteenth week they were potted up into 4 "- diameter pots, at which time the plants averaged about 8 "tall with basal stem diameters of about

3 /s ". These were grown in 50% shade. Two year old plants in 10 "- diameter pots in full sun now are approaching 3 feet in height with 3/4"-diameter stems.

FOUQUIERIÁ SPP.: The Fouquierias are also fairly easy once past the soft seedling stage, and again some seeds seem to be inviable. Fouquieria splendens grows very slowly even with copious watering and feeding.

Fouquieria macdougalii and F. digueti respond to generous treatment. The former at least will flower in two years, at which time it can be a nicely branched plant 2 feet tall. When grown hard, stem growth is much reduced and the plants develop relatively larger caudexes.

Seeds were sown in flats of 1:1 perlite:vermiculite on

June 8; germination was complete in less than a week.

Approximate germination was 50% for F. digueti and

F. splendens, but only 15% for F. macdougalii. (Seeds collected from cultivated plants of F macdougalii have been found to have much greater viability.) The seedling flats were treated weekly with fungicides named above and fer-

Minisymposium Propagation Techniques

209

A nursery flat full of Fouquieria macdougallii seedlings at the Arizona-Sonora Desert Museum.

tilized with 20 -20 -20 every other week. There was very little mortality. At 6 weeks the plants were moved into

21/4 " -diameter rose pots in well- drained soil and kept in the greenhouse under 50% shade.

JATROPHA SPP.: The Jatrophas are very easy to grow.

The only significant caution is to keep them quite dry during cool weather. In the heat of summer they will grow very fast with generous treatment, or remain as dwarfed bonsai -like specimens if grown hard and/or underpotted.

Seeds of 5 species were planted on June 8 in flats of 1:1 perlite:vermiculite in the greenhouse. Germination was complete within 10 days: species collection number number germiplanted nating j. macrorhiza Southeastern Ariz. 9/78

J. cuneata Hermosillo, Sonora 9/79 j. cerci f oli um

A. S.D.M. (cult.) (10/79

J. vernicosa La Paz, Baja Calif. 1 P79

J. cinerea

Bahia de Los Angeles

Baja California 11/79

4

11

20

5

76

3

71

1

5

0

All the seedlings were planted into 3 "- diameter pots in well- drained soil at 3 weeks of age and moved outside under 50% shade 2 weeks later. Fungicides were used weekly until the plants were moved outside. Fertilization is done bimonthly with a balanced fertilizer. Survival has been essentially 100 %. At 10 weeks the j. cinerea and

J. vernicosa plants averaged a foot tall with a basal diameter of about one -half inch. The J. cuneata plants were about 8" tall and 1/2" thick. They probably would be larger if they were in larger pots. These plants have vigorous root systems.

Germination of Agave, Yucca, Nolina and Similar

Plants (Information courtesy of Marc Mittleman, Desert

Botanical Garden, Phoenix). The Desert Botanical Garden has concentrated much of its effort in growing those plants that are not represented in the garden, primarily leaf and stem succulents. We have also placed a large emphasis on growing plants for our plant sales and on growing species that have restricted ranges. Agave arizonica and Agave toumeyana var. bella are two plants in the latter category. These two Agave species were grown from seed planted in October of 1977 and were about ready to go into the ground at the end of 1980.

Yucca glauca, Y. decipiens and Nolina longifolia have also done well from seed. Seeds of these were collected in the summer of 1979 and planted the following January.

Germination occurred anywhere from two to three weeks after sowing. All are now well established in deep 21/4 inch wide liners and are ready to be transplanted up to

1 -gallon cans.

The garden has had great success in starting all of their seeds in a mixture of 50% vermiculite and 50% perlite. As these were started in winter they were set on a heating pad at a temperature of 78 °F. They were watered daily with a fine mist until germination, at which time watering was reduced to every other day. Three weeks following germination, seedlings were thinned and transplanted up to deep 21/4 -inch liners. At the end of 1980 they were ready to transplant up to 1 -gallon cans. The mixture used for transplanting leaf succulents has been that of 2 parts decomposed granite to 1 part each of sand and compost.

About a tablespoon of the 12 -14 month formulation of

Osmocote® fertilizer is added to each gallon can. Aloes,

Dasylirions and many of the Crassulaceae have also responded favorably to these propagation methods.

A Radical Departure in Propagating Prickly Pear Cacti

(Information courtesy of R. E. Foster, Department of Plant

Sciences, University of Arizona). The University of Arizona's planning for an "Energy Ranch" prompted a number of proposals in the realm of renewable energy sources. One of these was the consideration of the Prickly Pear (Opuntia spp.) in a multiple use program. The plant is adapted to desert environments. It has been used for human food and for livestock feed. In some species the potential for rapid and massive growth makes the plant a prime desert candidate for biomass production with either methane or ethanol as an end product. The perennial characteristic suggests uses in erosion control especially in conjunction with land sculpturing for water management. Plantings could be made according to natural water availability. The establishment or renewal of Prickly Pear selections would call for rapid exponential vegetative reproduction.

Quick reproduction is not possible with the accepted methods. All information sources discovered called for the use of mature pads. All suggested that excised pads be allowed to air dry and form callus for about 1 month before being planted for adventitious root development. An extreme change in the time requirement and in other features seemed to call for radical changes in methods.

The procedure developed for vegetative propagation of

When cuttings are taken from large mature cacti with white hair in the form of a cephalium or pseudocephalium, propagants may be induced to not revert to a more juvenile stage if the physiological balance of the piece severed is little disturbed, quickly rooted and given good sun. The plant of

Cephalocereus leucocephalus illustrated here is such a specimen which has continued to produce hairs over a period of several years while grown as a container plant at the Arboretum.

muskmelons was adapted for Opuntia reproduction with surprising success. Various experiments were made.

Research demonstrated that juvenile pads (4 -6 cm long,

3 -4 cm wide, 5 -10 g.) placed in an aerated balanced nutrient solution plus growth regulator woiild start producing roots in 2 -3 days. These plants could be transplanted to soil in 15 -20 days with over 90% success. The results were similar for all species tested. With a spineless ornamental form (used because it was available and easy to handle) the third "vegetative generation" produced roots 170 days after the first padlet was treated. As an interesting spin -off it was found that an Opuntia plant could be grown to -large size with several mature pads in aerated water culture alone. Remember this is a desert loving plant regarding which the admonition if often heard by gardeners not to overwater.

Linda Moore demonstrating the electric carving knife technique at Tanque Verde Greenhouses.

The Electric Carving Knife Technique for Commercial

Cactus Propagation (Information courtesy of Carol Scannell, Tanque Verde Greenhouses). Tanque Verde

Greenhouses in Tucson, Arizona grows and markets cacti and succulents in sufficient quantity to satisfy local retail demands and to fill wholesale requirements of various nurseries and chain stores. Although a large number of cacti are marketed as small plants grown from seedlings, some are grown from cuttings taken from stock plants.

Some of these plants are ones which do not readily produce seeds or do not come true from seed.

When making a large number of cuttings at one time, several factors are important. 1) It is desirable not to have to move stock plants, but rather to cut them in place. 2) It is desirable that the cutting tool have a long blade and long handle. 3) It is good to avoid the "sawing action" of mov-

212

Desert Plants 2(4) Winter 1980 -81 ing the hand back and forth because spines are more apt to pierce the flesh if the hand bumps into a plant. 4) A serrated or sharp edge on the cutting tool is necessary to insure that the vascular bundles are quickly and neatly severed. 5) If fatigue of the fingers develops, efficiency at which consistently good cuttings are produced may decrease.

Although horticultural supply houses market a variety of "cutting knives" or "propagating blades," we have found that an electric carving knife best fills our needs as a commercial grower. By using this device the cuttings are uniform and of consistently high quality. In conjunction with the device, a pair of kitchen tongs (such as are used for grasping hot vegetables from boiling water) is useful for holding the part of the cactus which is being cut away from the stock plant.

Germinating Seeds of Wildland Trees and Shrubs (Information courtesy of Department of Plant Sciences

Faculty, University of Arizona). Many common crops which man has grown over the centuries tend to have seeds with simple germination requirements. Indeed, ease and constancy of germination under agricultural conditions have undoubtedly been selected for in plants which man has grown for a large number of generations. Wildland species, on the other hand, have seeds which often must endure extremely harsh environmental conditions. Such conditions are rarely as optimal for completion of the generalized plant life cycle as are those of the typical cultivated field. Such wildland or "native" plant species have become individually closely attuned to some set of specialized growing conditions.

Indeed, many wildland plants are so well adapted to specific environments that somewhat paradoxically they grow poorly or not at all under less harsh or more generalized conditions. Seeds of wildland plants may exhibit inhibitors or dormancy factors of complex biochemical derivation which are triggered by equally complex ecological sequences.

Seed testing laboratories mantained by governments or private companies are usually set up to deal with standard agricultural species. They will report germination percentages according to established national or international standards. Such testing laboratories often have little time or inclination to experiment with breaking dormancy in non -standard species. Seed testing and germination enhancement for wildland plants have been very capably treated recently in a U.S.D.A. (S.E.A.) publication by

James A. Young, Raymond A. Evans, Burgess L. Kay,

Richard E. Owen and Frank L. Jurak (1978). Previously,

N. T. Mirov and C. J. Kraebel (1939) had published a useful booklet on collecting and handling seeds of wild plants under auspices of the former Civilian Conservation

Corps. Dara Emery (1964) treated seed propagation of native California plants in a leaflet issued by the Santa

Barbara Botanical Garden. Otherwise, information has been quite scarce.

AFTERRIPENING. Some seeds such as those of Saguaro

(Carnegiea gigantea) or Palo Fierro Ironwood (Olneya tesota) germinate readily upon falling to the ground if other factors are favorable. A large number of species, however, may require an "afterripening" period. Often nothing more than holding the seed in a resting stage for six months is required for afterripening. In studies conducted within the Sonoran Desert, data tend to indicate that afterripening may be enhanced by the high ambient air temperatures characteristic of that desert. Investigators working further to the north have described a type of temperature -regulated afterripening whereby seeds of certain species germinate readily at low temperatures but not at medium or higher temperatures until afterripening has occurred. These investigators have found that low temperatures "are more likely to produce germination than higher incubation temperatures for seeds with after ripening requirements." They also point out that low temperatures also reduce growth of harmful microorganisms.

INHIBITORS. Seeds may contain chemical germination inhibitors which must either be washed away with water or leached with organic solvents. The presence of water soluble inhibitors in the seeds of desert plants assures that germination will not occur in nature unless abundant rain has fallen which will allow the seedlings to become well established. When washing inhibitors from seed coats, cold water is usually used because warm water might trigger germination.

SCARIFICATION. Many desert plants have tough impermeable seed coats, sometimes waxy. In nature seeds of

Palo Verde (Cercidium spp.) and several other species of the Legume Family do not ordinarily germinate until they have been washed by flash floods down normally dry washes. After the seeds have become abraded on the sand and gravel of the wash, they begin to imbibe water. If there was not enough rainfall to result in heavy run -off and the seeds travelled only a short distance, the abrasive action may not have been sufficient for water imbibition to occur. Here again an adaptation seems to exist to assure that germination occurs only when environmental conditions favor seedling establishment. To grow such plants under nursery conditions, it may be necessary to artificially scarify the seed coats. Most commercial growers soak the seeds in concentrated sulphuric acid, the length of time depending on the plant species. Other techniques which may prove to be effective but which may take more time and therefore be suitable for only small lots, include holding the seed with a pliars against a grindstone, rubbing the seed against sandpaper, or scratching the seed with a three -cornered file. Care must always be taken to avoid contacting the embryo. Soaking seeds in water which has just been brought to a boil may render the seed coat permeable and may also leach away some inhibitors.

STRATIFICATION. Classically, stratification refers to placing seeds in strata of moist sand outside or in a cold frame over the winter. As stratification is practiced today, seeds are usually placed with moist sand or vermiculite in plastic bags and stored in the refrigerator for one month or more. Growers of the many wild Penstemon species have found that length of time for stratification can be reduced

Minisymposium Propagation Techniques

INITIAL TEST AFTER

COLLECTION

IF SEED GERMINATES NO

FURTHER TREATMENT

11..

AFTERRIPENING

IF SEEDS FAIL TO

GERMINATE OR

IF GERMINATION IS

LIMITED, KEEP REPEATING

TEST TO SEE IF AFTER -

RIPENING IS SATISFIED

WITHOUT FURTHER

TREATMENT

SEED IMBIBE WATER

BUT DO NOT GERMINATE

SEEDS FAIL

TO

IMBIBE WATER

I

LIGHT I L-____--J

I

L r

STRATIFICATION

J

I

L

HOT WATER SEEP

J

MECHANICAL OR ACID

SCARIFICATION

-

SEEDS NOW IMBIBE

WATER BUT FAIL TO

GERMINATE

L

ETHYLENE ENRICHMENT

_J

GERMINATED

SEED

WASHING- REMOVE

L__

INHIBITOR

L_1

INTERACT /ON

I

NITRATE ENRICHMENT

L---

- - -

--1

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GIBBERELLIC ACID

ENRICHMENT

ENHANCEMENT

INTERACT /ON

COMPARTMENT

J

Flowsheet outlining steps for experimenting with germination of seeds of wildland plant species. Courtesy of James A. Young, Raymond A. Evans, Burgess L. Kay,

Richard E. Owen and Frank L. Jurak, from USDA (SEA)

ARM -W -3. By permission.

by placing the moistened seed directly into the freezing compartment of the refrigerator. Most plants of warm deserts do not have seeds which require stratification.

Plants of cold deserts often do, however. Aside from the typical cool -moist stratification, some seeds respond to warm -moist treatments or a combination of warm -moist and cold- moist. Stratification seems to relate to the penetration of oxygen through the seed coat to the embryo.

At colder temperatures oxygen- enriched water becomes available to the embryo and the colder temperatures reduce the oxygen demands of embryonic respiration, resulting in the oxygen -rich environment conducive to germination. Stratification therefor is essentially the same as oxygen enrichment.

CHEMICAL ENHANCEMENT. Chief among chemicals used to enhance germination are 1) thiourea and related sulphydryl compounds, 2) ethephon, 3) nitrate, generally in the form of potassium nitrate, and 4) the growth regulator gibberellic acid. Thiourea is frequently used in a standard three percent solution. [This potentially dangerous chemical should not be used by persons lacking training in use of hazardous chemicals. ] Ethephon functions as an ethylene gas generator, being merely added to the solution or substrate in which the seeds are placed. Potassium nitrate is often used as an 0.2 percent solution. Gibberellic acid up to about 250 ppm can be used in conjunction with the nitrate treatment. The combination of the two is frequently more effective than either substance used alone.

HEAT AND LIGHT. Seeds of different species show different rates of germination at various temperatures.

Although it is possible to determine the optimum germination temperature for a specific species by conducting a large number of separate experiments at different temperatures, a temperature -gradient plate can be used to more rapidly identify the best response. Such a device can be constructed to produce a constant change in tempera-

213

214

Desert Plants 2(4)

Winter 1980 -81 ture from one end to the other and this can be varied by means of manual controls. Seeds are then positioned regularly along the device for inducement of germination.

Some seeds, such as those of Saguaro (Carnegiea gigantea) require light for germination. They are customarily sowed on the surface of flats and a thin layer of chicken -grit broadcast over them. The grit must be widely spaced enough to allow some penetration of light to the seeds. As germination procedes, particles of grit are moved by the emerging seedlings and light penetrates to any individual seeds which previously had insufficient light.

Generally fluorescent light is considered superior to that from incandescent bulbs. In a greenhouse situation, the light entering from outside is sufficient. In growth chambers without natural light, eight hours of artificial light per day is recommended.

REFERENCES. 1) Emery, D. 1964. Seed propagation of native California plants. Santa Barbara Botanical Garden

Leaflet 1(10): 81-96. 2) Mirov, N. T. and C. J. Kraebel. 1939.

Collecting and handling seeds of wild plants. U.S.D.A.

Civilian Conservation Corps. Forestry Publ. No. 5. 3)

Young, James A., Raymond A. Evans, Burgess L. Kay,

Richard E. Owen and Frank L. Jurak. 1978. Collecting, processing, and germinating western wildland plants.

U.S.D.A.- S.E.A. Publ. ARM -W -3.

The Hammer Technique For Breaking Dormancy in

Gourleia (Information courtesy of Sarah Ives, V & P Nurseries, Inc., Mesa, Arizona). The trees of Chilean Palo

Verde (Gourliea decorticans) at the Boyce Thompson

Southwestern Arboretum flower well but produce quite variable and undependable quantities of seed. Although the species is in the Legume Family, the structure of the fruit departs radically from the typical legume pod, being round and fleshy with a hard stone -like center. This modified fruit resembles the drupe characteristic of so many plants in the Rose Family. Some of the seeds produced at the Arboretum are aborted and not suitable for propagation. To identify good seed the fruit can be shaken. A rattle often signifies that a good seed is within. The seed seems not to be attached to the inner woody shell at maturity.

The woody shell is so hard and impervious to water that it must be physically cracked. A hammer can effectively be used to crack the shell. Care must be taken not to crush the seed itself. Sowing can be done in flats and the seedlings transplanted subsequently into rose pots or any other deep container which allows the deep root system to develop. When roots become visible at the drainage holes the plants are ready to transfer to 1- gallon nursery containers.

About half of the seedlings grown from Arboretum seed are usually albino, coming up perfectly white.

Results of Germination Enhancement Trials With Certain Xerophytes (Information courtesy of W. R. Feldman,

Department of Plant Sciences, University of Arizona).

Seeds of arid -land plants were germinated as part of the laboratory portion of a class in nursery management taught in the Department of Plant Sciences. Various experimental treatments to enhance germination have been studied. Some of the data recorded for specific plants are given below. Treatments used in these studies included

1) mechanical scarification with sand paper (MS), 2) acid scarification (AS), 3) immersion in just- boiled water with soaking for 12 hours, or hot water soak (HWS), 4) placing in boiling water and soaking for 12 hours (BWS), 5) cold stratification of imbibed seeds at 35 °F for 6 to 12 weeks

(CS), and 6) no treatment (NT).

Seeds treated by stratification include Ephedra viridis,

Cupressus arizonica, Vitex agnus- castus and Prunus virginiana demissa. Non -treated Ephedra seed had not emerged at 5 weeks, with 60% emergence for those stratified 6 weeks. Vitex seed emerged at the rate of 15% for NT seed and 100% for CS seed stratified for 3 months.

Prunus seed stratified for 3 months had 90% emergence.

Mountain Mahogany (Cercocarpus) had 60% emergence for fresh NT seed in 1977 but only 25% emergence for 1 year old NT seed in 1978. When the 1 year old seed was stratified, however, emergence was 50 %. Cupressus arizonica had 50% emergence for CS seed in 1978. Seed of

Cat's Claw Vine (Macfadyena unguis -cati) planted in early September, 1978, (NT) had very poor emergence until November when night -time temperatures had been in the 40s for 2 or 3 weeks, at which time most of the seed emerged, indicating that they perhaps need a period of cold stratification.

For experiments with scarification, results were as follows: Dasylirion wheeleri, NT= 0 %, MS= 40 %, BWS=

60 %; Cassia artemisioides, MS = 100 %; AS = 90 %; BWS

= 0 %; Pittosporum phillyreoides, NT = 8 %; MS = 90 %;

Rhamnus californica, NT = 15 %, MS = 25 %; Rhamnus crocea var. illieifolia, NT = 10% MS = 15 %; Dodonaea viscosa, NT = 0 %, BWS = 10 %, MS = 100 %; Sophora secundiflora, NT = 0 %, BWS = 0 %, MS = 100 %. Stored seed of either Rhamnus studied may require cold stratification.

Mist -House Propagation of Succulent Euphorbia

Species (Information courtesy of Frank S. Crosswhite,

Boyce Thompson Southwestern Arboretum).

J.

E.

Thompson, Jr., nephew of the founder of the Arboretum, together with scientists at the Boyce Thompson Institute for Plant Research in New York, pioneered studies of adventitious root formation in plants under intermittent mist using growth regulators. This type of propagation is now routine throughout the nursery industry for many woody shrubs and trees as well as herbaceous perennials such as Penstemon. A number of commercial rooting powders or liquids are now available which contain growth regulators in standard concentrations.

Although now a standard procedure for woody species, propagation under mist has not been recommended for succulent plants because of the tendency of cuttings of the latter to become quickly necrotic in a substrate which remains moist for any considerable period of time. During

1972 a large number of succulent Euphorbia tirucalli plants were propagated from cuttings placed into dry soil mix. As is frequently the case with Euphorbia cuttings, rooting was slow and a few cuttings dried up before rooting -out. As watering was slowly increased and the

Minisymposium

Propagation Techniques

215 cuttings were presumably rooting, one particular plant stood out because of its turgidity, dark green, lush growth and generally robust appearance. When it was discovered that the container for this plant was "defective" in that it lacked a drainage hole, the idea was conceived of experimenting with radical departures in rooting Euphorbia cuttings, using the assumption that a moist relatively sterile environment would be desirable.

During 1973, when a large number of Penstemon cuttings were being rooted in the mist -house which remained after J. E. Thompson's studies previously alluded to, representative cuttings from all available Euphorbia species were subjected to experimentation using various mist house routines and growth regulator treatments. One technique resulted essentially in 100% rooting in 2 -4 weeks without necrosis of tissues. This procedure has been used effectively in mass -producing Euphorbias for annual Arboretum plant sales and is described below.

Take apical cuttings of Euphorbia 4 -8 inches long using .

a heavy and sharp pruning shears. Avoid contact of the poisonous sap with eyes or face. Place each cutting into a pail of water as it is taken. When the pail is full, go to a water tap and thoroughly wash latex from the cut surface of each individual cutting. Shake each cutting to eliminate excess moisture and dip the cut end into any of the commercial rooting powders having napthalene acetic acid and/or indole -3 butyric acid. If the preparation does not already include a fungicide, this can be blended -in before use. Place the cuttings into rose pots and fill with clean horticultural grade perlite. Place the pots under intermittent mist.

During cool weather, heating cables or propagating mats may be used to maintain a bottom heat of 70 ° -80 °F. The time clocks should be set to provide a one -second misting every three minutes during daylight hours and a few seconds of misting during widely separated intervals at night.

This method has never failed over several years and has proven quite successful with other genera of the Euphorbiaceae family such as Synadenium and Pedilanthus.

Once the cuttings are rooted they should be removed promptly from the mist -house to avoid hard water encrustations from forming on the stems.

The Shaving Mug and Brush Procedure For Rooting

Cuttings of Large Columnar Cacti (Information courtesy of Frank S. Crosswhite, Boyce Thompson Southwestern

Arboretum). Prepare a mixture of equal parts of 1) powdered sulphur, 2) fungicide powder, and 3) commercial rooting powder. Place into a large mug, adding water to make a thin creamy paste. Take apical cuttings 1 -2 feet long using a pruning saw. Hold each piece being severed with a loop of thick cotton rope. While the surface of the severed piece is still freshly cut, daub the sulphur fungicide- rooting paste onto the surface using an old fashioned shaving brush. As each cutting is treated, turn it on its side to air dry. After a few hours of drying, store each cutting in a vertical position in a plastic nursery container having a thin layer of vermiculite in the bottom. Large heavy cuttings will remain vertical if the cut at the base is perfectly at a right angle to the long axis and the nursery container is chosen to be so snug that the cutting touches on all sides. Cuttings should be stored vertically in 50% to

95 % shade for one month before watering. When watering finally commences, it can be repeated first at weekly intervals, then every 2 -3 days. When the vermiculite has been invaded by a large mass of roots, the cutting can usually safely be planted in a larger container with a good nursery soil mix.

If the cutting is stored horizontally the growing apex will tend to develop a disfiguring right -angle bend. If the cutting is placed directly into soil mix without the month -long callusing period, bacterial necrosis may develop. The sulphur in the paste dries out the cut surface rapidly and sterilizes the wound by forming sulphuric acid on the moist surface. The fungicide kills many of the organisms which might result in necrosis. The rooting powder provides hormonal growth regulators which induce rapid development of adventitious roots.

When cuttings are taken from large mature cacti, the rooted cuttings frequently flower the first year on the side which had faced the sun during the previous winter and spring, irregardless of the new orientation of the cutting (see illustration on cover of this issue). When a cutting of a mature columnar cephalium- bearing or pseudo cephalium- bearing species is rooted, quite frequently hairs of the structure will continue to grow and flowering will occur if the physiological balance of the piece severed is little disturbed, and if the piece is quickly rooted and given good sun.

Propagation and Establishment of Welwitschia mirabilis. (Information courtesy of Chuck Hansen, Arid

Land Plants, Tucson.) Welwitschia is an unusual desert plant of an extremely arid and restricted region of southwest Africa, the Namib. It has been much studied by plant morphologists, anatomists and taxonomists because of its unique structure and position in the plant kingdom. The plant forms two leaves during its lifetime and these lie on the surface of the desert sand with the reproductive structures between them. A plant is said to live one hundred years or more and the old leaves eventually become split into many segments. The plant is of great value in living collections of educational institutions and is a thought provoking conversation piece in private collections. Unfortunately its use has been restricted by knowledge of propagation procedures being not well publicized.

Taxonomically Welwitschia is a member of the Gymnospermae, the group which contains cycads, pines and

Ephedra, seed plants which do not have true flowers.

To propagate Welwitschia, obtain a 6 -inch diameter drainage tile (sewer pipe) of fired red clay to be used as a deep pot. For optimum results the drain -tile should be four feet deep but in any event at least two feet. Choose a clay flower pot that will just fit inside the tile and cement it in place in the bottom of the drain -tile. Place two inches of coarse material in the bottom of the pot and fill the tile with a mixture of 2/3 pumice and a/3 commercial potting soil to a level two inches below the rim. Place a thin layer

B

The unusual gymnosperm Welwitschia mirabilis of the

Namib Desert of Africa, as illustrated in the monograph by A. W. Eichler in Engler and Prantl's Die Naturlichen

Pflanzenfamilien (1889). A: young plant. B: old plant with split leaves. Successful propagation and growth can be achieved by planting in a tall drainage tile to accommodate the deep root.

of pumice (1/2" -1/4") over the soil mix. Water well and let drain. Remove the membranous wing from the seed. Dust the seed with fungicide such as Thiram® and place it directly on the pumice surface. Cover with a 1/2 -inch layer of pumice and mist lightly. Cover the top of the drain -pipe with glass or saran wrap. If the seed is good, germination should occur by one week. Remove the cover when the seedling is well above ground and move the drain -tile into bright light. There is a danger that the rapidly growing root may push the plant out of the soil. If the soil cornpacts at all or if the seed shows a tendency to heave, cover with additional pumice. Do not fertilize the plant for the first four months. Then water with a good well -balanced house -plant fertilizer at one -fourth the recommended strength on the package. Do not fertilize more frequently than once a month during the growing season of spring, summer and fall. The plant does well in the hardest light of a greenhouse. When grown in a home or patio situation, move the drain -tile out -of -doors in the summer and back indoors before the first freeze.

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Arboretum Progress

Robert T. McKittrick

Boyce Thompson Southwestern Arboretum

McKittrick

Arboretum Progress

This quarterly report will by design lack a central theme and thereby acquaint the reader with a number of developments at the Arboretum.

Admission to the Arboretum

The hours and days during which the Arboretum is open to the public have been changed recently from those in effect since 1972. All of the public facilities of the Arboretum are now open from 8:00 a.m. until 5:30 p.m. daily throughout the year except for Christmas Day. All public facilities are closed on that one day of the year. This is an increase of one hour each day and opens the Arboretum to the public on five holidays previously observed by the staff.

These changes bring the Arboretum's hours of public visitation into conformity with those of all other Arizona

State Parks which have programs which are predominantly interpretive.

In a move entirely unrelated to the above, admission fees were increased to $1.00 per adult visitor. Children

Tinder 17 years of age who visit the park under adult supervision are admitted free. It is hoped that the still nominal fee of $1.00 will significantly increase our revenue from that source and give some relief from our rising costs of operation.

Parking Lot

Desert Plants 2(4182 described the need for improved parking facilities and the master plan solution. The master plan proposes to replace three somewhat separated parking lots with one large one. The new parking lot would be located just inside the highway gate. A new foot trail would provide the visitor with a more beautiful and much less confusing approach to the visitor center and thence to the gardens.

At the September Advisory Committee meeting in 1980 the Boyce Thompson Southwestern Arboretum Board agreed to fund the engineering design for the parking lot.

The Arboretum Board has hired an engineer, soil testing has been accomplished, and a finished design should have been delivered by the time this is published. Cost estimates at that time will determine what future action will be taken.

Research

Comments on the Arboretum's 1979 -80 annual report appearing in Desert Plants 2(4181 touched upon the ground cover study now under way at the Arboretum under the direction of Dr. Charles Sacamano, Extension

Specialist and Horticulturist in the Department of Plant

Sciences of the University of Arizona. Pesented here is a brief but more detailed account of this most interesting and potentially productive study by Dr. Sacamano.

In the spring of 1980 a ground cover evaluation project was established at the Arboretum. Our interest in this group of plants is based on several important characteristics. Ground covers prevent soil erosion by wind and water in both traditional and arid landscapes. They also provide vegetative cover in rocky terrain and on steep, difficult to mow sites. Aesthetically, ground covers unify other design

218

Desert Plants 2(4)

Winter 1980 -81

View of an experimental plot at the Arboretum in which

Dr. Charles Sacamano and Leverett Clark of the

Department of Plant Sciences, University of Arizona, are conducting research on ground covers.

elements and introduce texture, color and scale in the ground surface treatment.

Despite an ever -growing demand for adapted and attractive ground covers, only a limited number of species and cultivars are available commercially in Arizona. Our project at the Arboretum is designed to screen promising ground cover candidates for growth rate, density, erosion control characteristics, heat and cold tolerance, insect and disease resistance, irrigation requirements and year -round appearance. To date, fifteen 3 -ft x 8 -ft plots have been established in the new Arboretum research area. All plots are now planted with test species provided by various western arboreta, Arizona nurserymen and the University of Arizona.

Ground covers that prove adapted and useful in southern Arizona will be publicized and recommended to nurserymen, landscape architects, and when supplies permit, to the home gardening public. A progress report on the performance of the first series of ground cover trials is planned for Fall, 1981.

A new study to collect, characterize and establish arid land legumes at the Arboretum has been authorized with initial funding provided by the Arboretum Board. Dr.

Lemoyne Hogan, Professor of Plant Sciences and Research

Scientist in Horticulture, University of Arizona, will direct this study. He described the study in the following paragraphs.

The Sonoran Desert has many advantages over more temperate, humid areas of the world, including more sunshine, less rainfall and warmer winters which are

Some of the promising ground covers being tested at the

Arboretum.

the primary factors contributing to the area's rapid population growth. However, these same desirable factors are responsible for our greatest problems, including 1) a deficiency of water for conventional irrigated agriculture,

2) the rapid migration of people from colder climates into the area with corresponding competition for scarce water resources.

New crops for agricultural use and for desirable environmental modification, as well as for revegetation purposes on disturbed land must be developed. Only the grasses are more important to man than the legumes.

Members of the Leguminosae family are extensive and the arid members of this family have been greatly under

exploited. There are thousands of little -known arid legume species that should be collected and established for research and study. They have much promise for producing very large increases in food proteins, forage for domestic animals and water conservation under arid urban environments. We in Arizona are in the position to take the lead in the development and utilization of desert legumes. The objectives of this proposal are enumerated below.

1) To assemble seed or other propagules of arid land legumes which are little known in Arizona, but which offer considerable potential for becoming important renewable natural resources in the arid Southwest. 2) To compile information on each introduction as to its requirements, uses and potential. 3) To establish at the

Arboretum either in the research area or public areas those species with the most potential.

(AN ANNUAL READER PARTICIPATION

SUPPLEMENT TO DESERT PLANTS)

Living with

Desert Plants

Through the

Year

AWARDS OF $50 UNITED STATES SAVINGS BONDS.

In general, the major articles published in Desert Plants are written by persons who work with desert plants every day. To provide a forum for increased reader participation, including persons who may or may not work with plants as a profession, this series is being established.

Material submitted for this series should be written in cameo essay style and should be limited in subject matter to some aspect of using desert plants. When an essay is selected and published in the "Livin

With Desert Plants Through the Year" series, the author will receive an award $5- United States Savings Bond. Employees of the Boyce Thompson Southwestern Arboretum may submit essays but are not eligible for the award. Unsigned essays will be produced by the editor. All essays published become the property of the Boyce Thompson Southwestern Arboretum and may be reprinted in book form.

CONTENTS OF THIS ISSUE

Landscaping With Wildlife in Mind

Holding Soil on a Bank With a Feather Duster

A Living Fence of Ocotillo

Attract Hummingbirds by Planting Shrubs and Herbaceous

Perennials Having Flowers in the Red -Yellow Segment of the Color Spectrum

Environmental Restitution as a Hobby

Transplanting Creosotebush

Grow an Extra Room for Fresh -Air Living

Seri Ironwood Carvings

Cut the Heat Load and Cut the Cooling Bill

Heating the House With Wood of Mesquite and Ironwood

Using the Ribs of Saguaro Skeletons

Growing Saguaros and Barrel Cacti From Seed

The Odor of Rotten Meat

Start a Collection of Baskets Made From Desert Fibers

Make a Lamp From Cholla Wood

Bunny Ears in Sheep's Clothing

Don't Let Leucaena From Oaxaca Cause Your Hair to Fall Out

Rather Than Drinking it, Why Not Bake it

For 76 Hours in a Pit in the Ground?

The Jojoba Revolution in Care of Skin and Hair

Using Aloe vera to Treat Burns

Does "Chaparra Tea" Have a Real Value?

It Melts in Your Mouth, Not in Your Hands

The Museum Theory; -- Subject Yourself to a Learning

Experience by Visiting a Museum of Living Plants

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LANDSCAPING WITH WILDLIFE IN MIND.

Growth of of cities in desert areas and encroachment suburbs into natural plant communities results in destruction of habitat for wildlife.

But even the most densely populated cities eventually develop a fauna linked to the plants which have been used in landscaping.

Where suburbs meet the natural desert or where dwellings have large yards, it is particularly feasible to modify the landscape to attract certain forms of wildlife or to discourage others.

Landowners frequently want to eliminate rattlesnakes and skunks. Skunks often are attracted by an abundance of insects for food, the insects often having been attracted by lights at night.

Rattlesnakes come in where mice, rats and other small animals are abundant.

Cutting down on outdoor lighting and using blackout shades or heavy drapes at windows can reduce the prevalence and crawling insects as well as skunks.

Domestic cats are often kept to keep of flying down the population of mice and rats but they also tend to kill birds, small rabbits and lizards.

Landscaping with plants which do not provide food for mice and rats will select against rattlesnakes as well.

Packrats, rabbits and porcupines can be scourges to desert gardeners.

On the other hand, songbirds, raccoons, squirrels, quail, doves, chipmunks and lizards are considered desirable by many suburbanites.

Although larger forms of wildlife such as deer, mountain lion, and javelina will bighorn sheep, particularly at night, they are far- ranging and little can be done by a bobcat come into suburban areas, small landowner

Desert to keep them on a particular property.

Hackberry (Celtis pal=ida) provides cover for small small wildlife and produces abundant edible fruits.

Saguaro

Cactus

(Carnegiea gigantea) has spines oriented to discourage damage to the plant by javelinas, packrats and rabbits and is an important provider fruit for wildlife in summer.

of

Where rabbits and packrats are abundant it is difficult to grow less spiny forms of cacti, succulents

Desert Penstemon or herbaceous perennials.

(P. parryi) can be used as a free- flowering spring perennial, however, since chewing animals often pass it by.

In general, long lived stiff- branched trees and shrubs are probably best at providing =excess of leaves, twigs and fruits for wildlife while retaining a quantity of biomass necessary to succeed in the landscape.

for the pl ants

Persons desiring to encourage particular forms of wildlife on their property should observe the animals in nature and do some detective work to discover the kinds of plants they use for food and cover.

HOLDING

SOIL

ON A BANK. 'WITH A FEATHER

DUSTER. The desert Feather

'Duster (Calliandra eriophylla) has small leaflets arranged pin of Mesquite.

Innately somewhat like those deed,

Calliandra is often cowboys as

"False

Mesquite" superficial resemblance to prostrate form of referred to by because of a more or a less

Mesquite which grows in

Texas.

The name "Feather more commonly used for

Duster," which is the plant, refers to the pink or whitish flowers with stamens clustered to resemble a miniature feather duster. The plant spreads by means of underground rhizomes to vegetation on hot dry banks. The mat of rhizomes and roots was form a virtual mat of recognized by Arboretum

J. Crider, formerly Head of the

Director F.

Department of Horticulture at the of Arizona, as

University of especial significance for controlling erosion of soil in the

Southwest.

He set up a cooperative nursery to grow and similar soil erosion control this plants at the Arboretum, a nursery staffed by cooperating government agencies.

This proved so successful that the federal government wanted to duplicate it elsewhere on a larger scale.

Crider resigned his position at the Arboretum to become one of the "founding fathers" of of the U.

S.

the Soil Conservation Service

Department of Agriculture.

Partly because of Crider's historic work at the Arboretum with Calliandra and similar erosion - control ground covers, the Arboretum is listed in the

National Register of Historic

Places maintained by the U.S. Department of the

Interior.

A LIVING FENCE OF OCOTILLO.

The Ocotillo

(Fouquíeria splendens) grows in the

Chihuahuan

Desert, Sonoran Desert andMojave

Desert.

It the Middle East, South can also be grown in

Africa, Australia and South America.

The many wand -like branches can be cut two or three making a feet above the ground and used for living fence.

begin.

Late summer is a good time to

In some jurisdictions (particularly

Arizona) a permit may be required to ensure that persons have legal ownership of any

Ocotillos which they cut. It is customary to cut 42 -foot long sections and to weave them with wire to resemble snow- fencing, the redwood lath being replaced by the

Ocotillo wands.

bottom ends of the wands all pointing fence is

Care should be same direction and that taken

The other end will not root.

to have in the the bottom end of the eventually planted in the ground.

As soon as the it is woven, the

Ocotillo fencing should be rolled up like a rug and stored upright in a dry shady place for two weeks to one month.

During this period the cut ends will heal over. While the fencing is curing, the fenceposts should be set into the ground eight to ten feet apart. Two strands of wire are then stretched tight and nailed on the outer side of the posts 12 feet and 3 feet high respecdug tively.

Then a one -foot deep trench is the fence line directly under the length of the wires. The soil removed should to remove roots, gravel and be screened trash, with the best 5/8 in volume saved and mixed with 1/8 sand, 1/8 perlite or pumice and mulch.

1/8 organic

This amended soil is then returned

The cured fencing can then to the to the

Each cane should be allowed to into depth.

trench.

be stretched along the fence line and wired two fence wires already installed.

the amended soil to settle down about one inch in

After two weeks the fence can be

Eventually the fence will lightly watered.

leaf out and new branches will grow at top and bottom.

Mature fences produce flowers.

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ATTRACT HUMMINGBIRDS BY PLANTING SHRUBS AND

HERBACEOUS PERENNIALS HAVING FLOWERS IN THE

RED- YELLOW SEGMENT OF THE COLOR SPECTRUM. In general, the red end of the color spectrum is most visible under (desert) conditions of high light intensities, whereas the blue end is more visible under (non- desert) conditions of low light intensity. In colloquial terms, the "hot" colors are at the red end and the

"cool" colors at the blue end.

There are red, orange and yellow oil globules in the cones of the retina of the hummingbird eye.

These effectively filter out the other colors of the rainbow so that hummingbirds are truly

"colorblind" to colors in the "cool" segment of the spectrum.

Within nature's animal kingdom both insects and birds are noted for feeding on the nectar secretions of flowers.

Within the insect hierarchy, those classed as bees are totally dependent for food on flowers, and within the hierarchy of birds the hummingbirds are equally dependent.

But interesting enough the commonest types of bees respond to the "cool" end of the color spectrum opposite that which attracts hummingbirds .

This allows man to modify his landscape to differentially attract either hummingbirds or bees.

Desert plants which can be used to attract hummingbirds include

Firecracker

Penstemon (P. eatonii). Desert Penstemon (P.

parryi), Chuparosa (Beloperone californicaj,

Desert Honeysuckle ZAni_sacanthus thurberi),

Ocotillo (Fouquieria splendens), Tree Tobacco

(Nicotiana glauca), and the many species of

Aloe.

In the Sonoran Desert hummingbirds used to be absent on migration during the winter because of a scarcity of winter -blooming native food plants.

Importation of Tree

Tobacco from South America and so many kinds of Aloe from Africa have made winter -blooming

Costa's Hummingbird (Calypte costae) pollinbird plants so commonplace that many humming ating Firecracker Penstemon (Penstemon eatoni). Drawing by Carol D. Crosswhite.

birds now spend winters in the Sonoran Desert, failing to migrate.

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SPECIAL SUPPLEMENT

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ENVIRONMENTAL RESTITUTION AS A HOBBY.

When a home is purchased or newly built or a mobile home placed on a lot, the occupant may wish to restore a portion of the environment to its original condition before bulldozers or construction trucks and heavy equipment modified it. If a person chooses to do this and enough land surrounds the dwelling, it is often possible to divide the landscape into three concentric zones,

1) that nearest the home where native and introduced desert plants with domestic functions are planted, 2) a transition zone, and 3) an outer zone where the original desert has been restored. Often the contractor has planted vegetation in Zone

1 according to specifications of a landscape architect. For Zone 3 to be properly restored a bit of detective work may be necessary to determine the phytosociologic parameters of the original native plant community which once was present.

This phase of landscaping can very effectively be done by the landowner as a hobby over a long period of years.

Persons have done this effectively by studying model desert plant communities at the Boyce

Thompson Southwestern Arboretum.

Aside from several natural Sonoran Desert communities already present, model communities for other deserts are now on the drawing board for construction at the Arboretum. After a property owner has restored Zone 3, various enhancements

This or modifications not honestly fitting into Zone

3 can be established in Zone 2.

area of transition can benefit from desert plants which are not native to the area or from native plants in altered associations.

In this zone, where neither domestic needs nor natural associations are overriding factors, the landowner can experiment and express individuality.

This can be the place to try growing that fascinating plant seen on a vacation or business trip.

TRANSPLANTING CREOSOTEBUSH.

Although it is commonly stated that Creosotebush (Larrea tridentata) can not withstand transplanting, there exist nurserymen with "trade secrets" of how to do it.

A careful investigation reveals that

5- gallon size plants of this species favored by landscape contractors have often been dug.

The very common nature of this plant over so many square miles of Chi huahuan Desert, Sonoran Desert, Mojave Desert, and in South America, makes it a good species to transplant with little fear of making any substantial decrease in its abundance. Nevertheless, persons digging the bushes need permission of the landowner.

Although some of the trade secrets will perhaps always remain secret, some pointers can be given for persons who want to transplant a bush or two from areas where bulldozing is scheduled or from one part of their property to another. Transplanting is most successful from heavy clay soil which will hold together when wet.

The first rule for transplanting Creosotebush is to do it in the winter but to plan for it in summer.

Obtain heavy 5- gallon size plastic pails used in the construction industry.

During summer draw a circle around a small

Creosotebush equal to the pail's diameter.

Pour a bucket of water so that it soaks in within the circle. Repeat in one week.

With a deep and narrow spade the third week cut down at points along the circle a foot or more deep to sever many of the lateral roots.

Continue watering within the circle over the ensuing months to encourage internal root formation within the soil enclosed by the circle and eventually sever all remaining lateral roots.

If the plant looks healthy in mid -winter, cut half of the top away and remove the plant from the ground, making certain that the clay is moist enough to allow the root ball to remain relatively intact.

Place this root ball into the 5- gallon pail, filling any space as well as the top few inches with moist sawdust and fine wood shavings mixed with soil from the hole. Keep wet through the winter.

If the Creosotebush is alive in spring it can be planted safely with very high probability of surviving in its new location.

GROW AN EXTRA ROOM FOR FRESH -AIR LIVING.

Living plant materials can be manipulated just like cement blocks, lumber and other building materials. A blueprint can be drawn up just like that for masonry or wood construction.

For a landscaped "room" to be ready to use, however, it may need some time to grow.

An outdoor room can be furnished with a portable barbecue or a permanent brick fireplace, outdoor chairs, benches, lounges and tables. Or perhaps it could be the focus fora spa or swimming pool. The sides of such a room can be grown by planting the Australian

Acacia stenophylla five feet apart.

A shade roof can be grown by planting a tree of Chilean

Mesquite

(Prosopis chilensis) or Himalayan

Cedar (Cedrus deodara) in the center of the

"room" and cutting enough of the lower branches to allow walking under the spreading boughs.

There are numerous other possibilities which could be obtained from a landscape architect or which could be discovered by personal detective work to fit the particular type of

"room" which the landowner might want and which would be compatible with the land.

SERI IRONWOOD CARVINGS. Seri Indians living on the coast of Sonora, Mexico make beautiful hand - carved items from aged heartwood of

Ironwood (Olneya tesota).

These can be purchased directly from their makers in Mexico or in a few shops in the United States such as the gift shop of the Arizona State Museum operated by the

University of AriLcna in

Tucson. The carvings are usually in the form of various animals known to the Seri and are meticulously sculpted and polished with oil.

The wood is extremely hard, dense, heavy, tight - grained and red -brown in color.

It is so heavy that it will sink in water.

The

Ironwood tree grows in relatively frost -free areas where there is little concentration of cold at night resulting from cold air drainage from higher elevations.

The carvings are so expressive of the character of the wood and the Ironwood tree so characteristic of the

Sonoran Desert that a well- selected carving makes an exceptional conversation piece when used as a table centerpiece at dinner with guests.

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223

Mesquite (Prosopis velutina) is an excellent food and energy resource of the desert. It not only shades homes to make them cool in summer but lets light and heat through in winter. The hard wood is also a very good source of BTUs when burned. The beans are used as food by man and livestock and the flowers yield a copious nectar which bees store as honey. A: branch with pinnately compound leaves and flower clusters. B: pair of leaflets. C: flower. D: mature bean pods. Drawings courtesy of the College of Agriculture of the University of Arizona.

CUT THE HEAT LOAD AND CUT

THE COOLING BILL.

homes are frequently

In the Sonoran Desert cooled in the summer by refrigeration or by evaporative cooling.

The heat load from the sun can be reduced by painting buildings white, including the roof, the rays of the sun and by intercepting before they strike the

Trees of Mesquite (Prosopis) are building.

very good at shading buildings in the summer and letting the sun's energy through in the winter because, being deciduous, are present in summer the leaves and absent in winter.

the more completely

The colder the winter, deciduous are

Pear cacti the Mesquite trees.

Prickly

(Opuntia spp.) planted near the foundation of- outer house very effectively to walls can serve insulate that portion of the house.

Plants which cut heat loads to conservation are a promote domestic energy current area of investigation at desert research centers.

HEATING THE HOUSE WITH WOOD OF

MESQUITE

AND IRONWOOD.

With energy costs escalating, many desert residents are re- discovering the

BTU's locked up in wood of Mesquite wood. Ironwood dulls saws rather is not as abundant as Mesquite.

and Ironquickly and

Much of the land which supported Ironwood in central and southern Arizona was cut over and converted to Citrus groves and later to housing subdivisions and trailer courts.

Much of the mature Ironwood near civilization has resulted from stump- sprouting of trees cut at of the century for firewood.

the turn

Although Ironwood has apparently declined with increasing settlement, Mesquite has increased dramatically. Mesquite's historic increase is largely due to its being spread by cattle.

As Mesquite is cut for firewood it begins to grow back and so is a valuable renewable natural resource.

It makes one of the very best firewoods of the entire world.

It is good fireplaces and for use in Franklin stoves, outdoor grills.

At the turn of the century

Mesquite was considered valuable for firewood.

With the advent of cheap oil, gasoline, gas and electricity in natural this century, Mesquite became little used for energy and it took on a reputation of being a rangeland pest that was difficult to eliminate.

With Mesquite wood now again commanding a high price, ranchers have the opportunity to sell cutting rights by the cord.

Some jurisdictions now require a permit for the cutting of Mesquite or Ironwood to ensure that persons cutting permission of the landowner to do so.

it have

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224

USING THE RIBS OF SAGUARO SKELETONS. Since prehistoric times the wooden skeletons of

Saguaro cacti (Carnegiea gigantea), once the plants have died, have been broken apart and the vascular ribs trued up by a little whittling or sanding to be used in construction of walls, fences and ceilings

(often with addition of plaster or stucco) or in making a variety of household items.

They are good for making trellises and shade canopies, or can be used as poles for staking tomatoes; indeed use of Saguaro ribs in desert areas where the plants grow is ubiquitous.

Walk into Pete King's drugstore in Florence, Arizona and look for his diploma or pharmacist's license. Yes, the frame is made from Saguaro ribs.

Encounter a happy retiree enjoying a hike on the desert in the winter sun.

Yes, his walking stick is made from aSaguaro rib.

And what do ranchers prefer to use as spacers in fences between heavy posts?

You guessed it, -- Saguaro ribs.

Saguaro ribs are well suited for making a variety of craft items.

Chances are good that you can think of some entirely new use in your particular situation.

And all who see it will say "Why, you made that from Saguaro ribs, didn't you?

How imaginative!" How many times were those same sentences uttered in prehistoric times, and in how many languages?

Saguaro skeletons with exposed ribs were frequently illustrated in books written by people who had travelled to far -off Arizona in the nineteenth century. The ribs have provided an easily worked wood which has been used by inhabitants of the Sonoran Desert for making various utilitarian articles for centuries.

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

GROWING

SEED.

SAGUAROS AND BARREL CACTI

FROM

A recent article in the Smithsonian magazine focused on digging of cacti such as

Saguaro (Carnegiea gigantea) or Barrel (Fero cactus spp.) and its deleterious effect on the natural desert landscape.

These plants are protected by law in many jurisdictions, particularly in Arizona, but the harvesting of seeds is almost universally allowed.

a hobby,

As indeed even as a "good deed" to nature, persons should be encouraged to produce these plants from seed so that abundant material will eventually be available in future years for landscaping purposes.

Since this takes time, it is a long -term hobby.

Seeds are very abundantly produced by these plants and they germinate readily under proper con dtions.

Barrel cacti have golden fruits which can be twisted off in winter.

Split or cut the fruit open and spread the seeds out on a newspaper in the house to ensure that they are well dried before storage. The fruits of Saguaro split open, naturally fall from the plant in summer, and should be gathered at once so the seeds are not eaten by animals.

Since Saguaro fruits have a moist pulp, the seeds should be washed in water immediately and the clean seeds spread out on newspaper to dry.

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The Saguaro (right) and Barrel (left) are cacti of the Sonoran

Desert which are not readily propagated from has been recent publicity concerning the cuttings. There illegal digging of them for landscaping purposes without necessary governmental permits.

Although it takes a number of years for these plants to grow large enough for landscaping purposes, they are very easily germinated and grown from seed. Directions are given which should allow a person to grow specimens Zarge enough to plant out in about seven years from seed. Sketch by Carol D. Crosswhite.

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Since some mortality can be expected to occur during the years that will be needed to produce Saguaros and Barrels large enough to use in landscaping, it is advisable to start by germinating a large number of seeds.

A full nursery flat (18" x 18 ") of each species would be a good quantity to germinate.

To do this, build a box large enough to accommodate the number of flats desired on its floor.

The top and bottom should be made of plywood spaced 15 inches apart with all four sides left open to be covered with transparent sheet plastic after the seeds are sown.

Place the box under a Palo Verde or Mesquite tree on the north side of the canopy and begin germination in June or July.

Fill the flats

3/4 full with a soil mix of 1/4 peat moss,

1/4 vermiculite,

1/4 perlite and 1/4 sand.

fertilizer rated

A teaspoonful of slow -release at 8 -9 months duration should the soil of each flat.

be mixed into

Water each flat, let over the drain and sprinkle the seed evenly surface.

Sprinkle a thin layer of chicken grit over the seed so that some seeds still show and the layer is not more than one grit thick.

This can be achieved by watering the seed and grit together with a-misting nozzle on the end of a garden hose. Misting nozzles used in produce departments of grocery stores are about the right type.

The water should form a cloud with absolutely no drip until condensing on the seed and grit.

After settling the seed and grit together, the plastic sheeting should be tacked onto the box to produce a high humidity chamber.

Let the plastic hang free like a window shade on one side weighted down by a length of Saguaro rib stapled to the bottom.

Lift this up once a day to check on humidity and germination, repeating misting when necessary to keep seed moist and humidity high.

When most of the seed is up, cut down on misting, letting plants and soil dry out between waterings.

When seedlings nearly fill the flat, change to watering with a flaring rose nozzle and remove one of the plastic sides of the box.

Nine months after germination, separate the seedlings into clumps of 7 -15 each without disturbing roots within the clumps, then plug into 49 evenly spaced (7 x 7) holes in fresh soil mix in new 18" x 18" flats

(provided with slow-release fertilizer rated at 14 months or more).

A large number of "clump flats" can be produced from one seed flat.

After

14 -18 months, separate the cacti of each clump, placing large ones each into separate 24 -inch diameter square plastic pots and small ones in groups of

2 -3 in

2 -inch diameter pots.

Each succeeding year re -pot into larger containers, from 2 -inch to 24 -inch to 2 3/4 -inch to 4 -inch to 6 -inch (= "one- gallon" size) to

8 -inch or "two-gallon" size. The cacti should be large enough to plant for landscaping in about seven years from germination.

become highly branched and clustered.

Large old specimens are frequently seen on porches in desert regions.

When a person walks by a blooming Stapelia, suddenly the person thinks dead mouse or a piece of that there is a rotten meat somewhere nearby.

who have grown

Stapelia

Even people plants for years forget and may start looking for a dead mouse.

The odor carries for some distance and may completely permeate the air in closed quarters. It may take a long time for the person to associate the smell with the plant. The genus Stapelia and its relatives, rather than attracting bees blooming for pollination by producing nectar and a sweet fragrance, attract flies for pollination by duplicating the odor of rotten meat. The flies lay their eggs on the flower and in so doing carry

Stapelia pollen from the anthers to the

There are numerous relatives of but stigma.

Stapelia which are rare in cultivation in public which are sometimes displayed greenhouses.

Some of these

(moving) structures within the have vibrant flower which resemble writhing fly larvae.

These unusual plant parts further deceive flies into visiting the flowers and in combination with the foul odor guide the insects to the stamens and stigmas.

The genus Stapelia and its relatives are known as "Carrion

Flowers" in

English.

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THE ODOR OF ROTTEN MEAT.

Species of Stapelia from Africa are succulents generally quite attractive to humans in appearance but not in odor.

hairy.

The flowers are often huge and

When protected from frost, plants

Sketch of Starfish Flower (Stapelia nobilis) showing the erect stems, an unopened flower bud and an open putrescent flower.

Sketch by

Carol D. Crosswhite.

SPECIAL SUPPLEMENT LIVING WITH DESERT PLANTS

227

START A COLLECTION OF BASKETS MADE FROM

DESERT FIBERS.

The Papago Indians of the

Sonoran Desert make fine baskets using a coiled foundation of split Beargrass leaves (Nolina microcarpa) sewed with white (sun -bleached)

Yucca leaf strips, green (shade- dried) Yucca leaf strips, and black Devil's Claw (Proboscidea) strips from the fruit.

The sewing is done with either a split open stitch which leaves the Beargrass coils ".risible or a tight closed stitchwhich hides the foundation work.

Apaches make baskets using a foundation of

Never - Break -Bush (Rhus trilobata) stems sewed with strips of Willow (Salix) or Cottonwood

(Populus) bark.

These are frequently made waterproof by calking with Pinyon pitch. Seri

Indian baskets are made from fibers of Torote

(Jatropha), frequently dyed.

Hopi Indian baskets are made by different methods in different villages, including a loose weave of

Yucca for sifting, wickerwork and coiling.

Colorful designs in Hopi baskets are generally achieved by dying the fibrous strips before weaving.

Twill plaited baskets of split Sotol leaves (Dasylirion) are made by the Tarahumara

Indians of Chihuahua, Mexico without decorative colors and are obviously intended for everyday utilitarian use.

Baskets made from desert fibers by North American Indians are becoming less common and good examples command increasingly higher prices from collectors.

MAKE A LAMP FROM CHOLLA WOOD. The skeleton of Jumping Cholla

(Opuntia bigelovii) or

Chain -Fruit Cholla (O. fulgida) is cylindrical and consists of an attractive network of vascular tissue with intervening spaces.

A three -foot long section can be cut from such a skeleton, preferably incorporating some of the wider base of the plant.

The cylinder should be reamed out with a stiff brush attached to a pole.

The outer surface of the cylinder should be sanded with first coarse and then fine sandpaper.

Clean the crevices with the high pressure nozzle of a garden hose and if necessary pass a stiff bottle brush through the many spaces.

Select a board to use as a pedestal for the lamp, cut it to a desired size, do any carving or decorating desired, and drill a half -inch hole in the exact center.

Stretch a lamp cord through the cactus wood cylinder and through the hole in the pedestal.

Then center the bottom of the cylinder on the hole in the pedestal and nail the two pieces of wood together from the bottom of the pedestal. Attach a combination bulb socket and lampshade holder to the upper end of the cord and anchor it onto the upper end of the cholla wood cylinder. Varnish all wooden surfaces to display the g-,:oi n and character of the wood.

Place the l nshade on the holder and an electrical plug on the end of the cord.

Have an electrician or the electrical inspection department of the city or county check the lamp for safety.

After it has been criticized and you have made any suggested improvements, you are all set to make lamps as gifts for friends and relatives.

They make excellent souvenirs of the desert, once not at all uncommon but now rather rarely seen in gift shops.

Plant scientist George Engelmann used this drawing of the wood of Jumping Cholla

(Opuntia bigelovii) to characterize the newly discovered species 125 years ago.

Reproduced from the government document of

1856 entitled "Reports of Explorations and

Surveys For a Railroad From the Mississipi

River to the Pacific Ocean.

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228

SPE -..IAL SUPPLEMENT

LIVING WITH DESERT PLANTS

The Bunny Ear Cactus

(Opuntia microdasys) of the Chihuahuan

Desert has a polka dot pattern of glochids but lacks the long spines which most other species of prickly pear cacti have. Sketch by Carol D.

Crosswhite.

BUNNY EARS IN SHEEP'S CLOTHING. The English name for one of the commonest cacti sold for ornamental use is

"Bunny Ears" (= Opuntia microdasys) , a plant of the Chihuahuan Desert.

The plants are of the prickly -pear type with flat "pad- like" stem segments. A young plant grown from a cutting is normally sold at the stage when two new segments are emerging from the older one, the whole plant then having the appearance of a rabbit's head with ears.

Normal spines areoles are are entirely absent but the filled with many glochids of either white, yellow, chestnut -red, or cinnamon -brown coloration. The glochid patterns make the plants look like stuffed animals covered with polka dot cloth.

Other common

English names which forms of the plant go by are

Yellow

Polka Dots,

White Polka Dots,

Angel Wings, Cinnamon

Bear, or Hob -Nail

Cactus.

A person who has never encountered the species before usually strokes the surface as if petting an animal. Unfortunately, the glochids become embedded in the skin and cause what many persons describe as the most painful itching they have ever experienced.

After an initial encounter, people are loathe to touch the plant again in any way without gloves or tongs. But even among knowledgeable persons it remains a popular ornamental cactus when treated with respect.

communities in Sonora and can also be seen in yards in Arizona in Tucson, Casa Grande,

Superior, Yuma, and less frequently in Phoenix.

The plant has little natural resistance to freezing weather.

Recently, however, scientists have hybridized it with the Texas Lead

Tree (L. pulverulenta) to produce a variety which may possibly become economically important in the horse - latitude deserts which are characteristically colder than the natural home range of Leucaena.

In historic times this Aztec crop was spread through the world`s tropics.

U.

S.

soldiers saw young tender shoots being eaten by Vietnamese.

Leucaena has one drawback which scientists are trying to eliminate.

eaten exclusively

When the plant is without other foods to balance the diet, it causes the hair to fall out.

One sheep rancher in Australia decided to turn this fact to his advantage.

He fed his sheep on Leucaena, after which they could be sheared "with a simple stroke of the hand."

Unfortunately, the separation of the wool from the sheep was so complete that the animals had no protection from the sun and in true "Samson and Delilah" fashion became powerless to cope with their environment.

Readers are referred to the book Ieucaena,

Promising Forage and Tree Crop for the Tropics published by the National Academy of Sciences

(Washington, D.C.) in 1977 for further details of this almost unbelievable happening.

DON'T LET LEUCAENA FROM OAXACA CAUSE YOUR

HAIR TO FALL OUT.

Could this be a

Samson and Delilah story?

The state and city in

Mexico named Oaxaca have long been associated with Leucaena.

Indeed, the name "Oaxaca" is said to be an old Aztec word which can be.

translated

"place where

Leucaena can be found." Leucaena leucocephala is a tall shrub or small tree- in the Legume family.

Like Mesquite, it has pinnately compound leaves with many tiny leaflets.

The young legume pods can be boiled and eaten like

"green beans."

Livestock relish the foliage as a fodder. Leucaena apparently was a IvIeso-

American crop plant long before

Columbus discovered the New World.

It can now be found growing in yards of Latin American persons throughout the warmer parts of the

Americas.

In the desert it is coliuuon in

Branch of Leucaena leucocephala showing a spherical flower cluster in bud, the pinnately compound nature of the foliage, and two mature pods. Drawing by

Carol D. Crosswhite.

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

229

RATHER THAN DRINKING IT, WHY NOT BAKE

IT

FOR 76 HOURS IN A PIT IN THE GROUND?

persons know of the mescal

Most liquor bottled in the

Tequila district of Mexico.

Century

Plant (Agave) species are adapted to sites which are periodically very dry and these plants exhibit numerous "desert plant" adaptations.

The Century Plants are monocarpic, i.e. they flower once and die.

Just before certain kinds flower they are pried out of the ground and the leaves cut away so that only the heart remains, the latter resembling somewhat an oversized pineapple. These hearts are very high in carbohydrate which had been stored to allow growth cf a tremendous flower stalk. A sweet drink from the plant is known as "agua miel."

The juice can be fermented to produce an intoxicating beer -like drink

Distilled beverages are known as

"pulque." marketed under the name "mescal."

In some parts of Mexico a bottle can be purchased

Mescal con su

Proprio labelled

"Legitimo

Giisano."

In the bottom of the bottle is a worm, actually the larva of an Agave- boring insect.

This is added to prove that made from Agave rather than being a the mescal is "legitimo," i.e. that it is really watered down drink adulterated with Sophora or some other substance.

A premium mescal produced from a particular kind of Agave in a certain labelled "tequila," just as a district is particular kind of wine produced in a certain district of France is labelled "burgundy."

Although "mescal" is used as the name of a liquor, the same name is used for a nutritious food which can be produced from hearts of

Agave. Some kinds of Agave make a good mescal food but others are inedible.

Agave murpheyi is easy to grow from bulbils, i.e. little plants produced on the flowering stalk, and may be an ancient Indian cultivar of the Sonoran Desert.

It has been found near prehistoric Indian ruins, being originally discovered as a species new to science growing in a natural area at the Boyce Thompson Southwestern Arboretum.

Mescal food has been experimentally produced at the Arboretum from A. murpheyi using the Indian recipe of baking the heart in a covered pit in the

This slow "cooking" is ground for 76 hours.

done at a temperature low enough so enzymes are not de- activated that but hot enough to cause the carbohydrates to be converted to sugar. If not left in the heated pit long enough the food is reminiscent of sweet potatoes with an after -taste.

When "cooked" longer it tastes more like molasses.

Mescal food cakes similar to ones prepared by the

Tarahumara Indians of Chihuahua in

:istoric time have been excavated from pee. rstoric

Indian ruins in Arizona.

Perhaps scme day

Agave will be developed as a field food crop.

It is very resistant to drought and will grow in deserts with rather low annual rainfall.

Photographs of Agave murpheyi which accompanied the original scientific description of the species in the 1935 volume of the

Contributions From Boyce Thompson Institute photographer.

7

(i):

83 -85. Fred Gibson,

THE JOJOBA REVOLUTION IN CARE OF SKIN AND

HAIR.

Personal cleanliness in Homo sapiens involves the intentional use of water to bathe the skin and wash the hair. Invention of soap and later of various detergents and shampoos had a truly revolutionary impact on human cleanliness. But a relatively insoluble waxy form of "sebum" which is associated with hair follicles may become compacted when only common soaps and shampoos are used.

"Sebum" derives from the Latin name for tallow.

An extreme sebum problem is referred to as seborrhea, but minor problems are apparently' commonplace and have a significant impact on human grooming and appearance.

Recently it was discovered that a liquid wax from Jojoba seeds could be used to break up, dissolve, modify, condition and replace the sebum denosits. Companies which manufacture cosmetics, soaps and shampoos have conducted "proprietary" research, the details of which have been guarded from falling into the hands of competitors, and a number of patents have been issued. Many products in the personal grooming market are now beginning to incorporate Jojoba in their manufacture.

Jojoba enthusiasts believe that a new revolution is now occurring to put human skin and hair care into a third phase following the first phase of water use and the second phase of soap, detergent shampoo use.

The Jojoba plant is shrub native to and a desert the grounds of the

Boyce

Thompson Southwes tern Arboretum. The landmark discovery of the unusual liquid wax in Jojoba seeds resulted from a cooperative research project between the Arboretum and the University of Arizona.

230

SPECIAL SUPPLEMENT

LIVING WITH DESERT PLANTS

USING ALOE VERA TO TREAT BURNS.

The scientific name Zr-this plant indicates that it is the "true" (= vera) Aloe used for hundreds of years in medicine. It can be distinguished from other species of Aloe by the combination of its mature leaves being relatively toothless, gray -green, upright and without spots, and its yellow flowers pointing downward.

Many housewives feel that a plant or two of

Aloe vera ought to be grown within a few steps

76T-very kitchen.

Victims of serious burns should see a medical doctor at once, but traditionally Aloe vera has been used as first aid for a wide variety of burns.

One of the thick fleshy leaves is broken open to expose a succulent inner tissue which resembles Jello.

This gel is applied to the burn, care being taken that none of the hard outer part of the leaf scrapes across the burn.

Aloe vera has been used for treating grease burns, sunburn, and even the radiation burns which can result from cancer radiation therapy.

DOES "CHAPARRAL TEA" HAVE A REAL VALUE?

Recently an unusual calcium form of Vitamin -C manufactured at Prescott, Arizona was discussed on television as a possible breakthrough in treatment of arthritis.

Vitamin -C functions as an anti -oxidant but there is apparently some question as to the body's ability to fully utilize it in common chemical non - calcium configurations.

Persons who use "Chaparral

Tea" (actually made from Creosotebush leaves,

Larrea tridentata) for arthritis, rheumatism and as a tonic point out that Larrea leaves contain an unusual anti -oxidant, nordihydroguaiaretic acid (NDGA).

Creosotebush occurs on desert soils having a calcium carbonate

( "caliche ") layer.

Visitors to the Boyce

Thompson Southwestern Arboretum can observe natural "textbook examples" of its presence on calcium carbonate soils and absence from soils not having the calcium carbonate stratum.

Use of "Chaparral Tea" by health enthusiasts deserves further study by medical researchers.

IT MELTS IN YOUR MOUTH, NOT IN YOUR HANDS.

Euphorbia antisyphillitica was named for its use by cowboys and early settlers in the

Chihuahuan Desert and adjacent regions as a supposed preventative of syphillitic infection. In an unusual twist of history it later became used by millions of people in the

United States, Mexico and elsewhere around the world for a quite different reason. Perhaps most readers of this paragraph have consumed a substance from this desert plant.

Where the plant is native in Mexico harvesters make treks out to the hills where it grows and rip it up, roots and all, from the desert.

The plants are bundled and lashed high on the backs and sides of burros to be transported to a camp in the desert where they are boiled in water to which sulphuric acid has been added.

A wax from the plant forms as a scum on the surface.

This is raked off, thrown into buckets and taken to Candelilla wax collection centers to be purified.

This edible wax remains hard under conditions of high heat and humidity as opposed to chocolate and other coverings of candies and confections which stick to wrappers and hands.

Because the wax is water soluble it has been widely used as a covering for pellet -sized gums and candies which "melt in your mouth, not in your hands." Although chocolate bars are popular in cold regions or in winter, the

Candelilla wax covered items have proven more marketable in hot desert regions or in summer.

THE MUSEUM THEORY;

--

SUBJECT YOURSELF TO

A LEARNING EXPERIENCE BY VISITING A MUSEUM

OF LIVING PLANTS.

Botanical gardens and arboretums are classified as museums of living plants.

They teach in a subtle way by means of the museum theory.

It is possible for everyone, from the most ignorant and undereducated child to the most knowledgeable professor or technical researcher to learn more about desert plants and their place in nature's landscape by visiting an appropriate living museum.

A museum is a unique kind of institution devoted to the encouragement of learning and research in a special field of knowledge. When the botanist John Tradescant in England first used the term "museum" in its modern sense for his collection of materials assembled to invite study and research, he resurrected the word from its classical use to describe the temple of the seven daughters of Zeus, each daughter or "Muse" residing there having been regarded in Greek religion and mythology as having the capability of filling a respondent with knowledge in a particular branch of art or science.

The theory behind the establishment of museums is that the objects assembled and displayed fill the visitor with knowledge.

Thus the museum represents the ultimately pragmatic form of education: people will learn or do fruitful research if the very best materials underlying a branch of knowledge are assembled and made available under inviting circumstances.

How better to learn than to be filled with knowledge by materials having a substance so real, pure and attractive as one of the daughters of Zeus! In a museum the materials themselves teach and inspire.

Curators of museums provide structure and guidance to the collection, assemble it, make it available for study, and interpret it.

Such persons, although highly specialized teachers and researchers, are the keepers of the daughters of Zeus and of the temple, providing the circumstances for the union of respondent and

Muse with the intention that the appropriate daughter of Zeus (i.e. the substance of the collection) will be instilled into the communicant to fill that person with true and lasting knowledge of benefit in life. Although it is considered grammatically incorrect to say that a student is learned by a teacher, the unique passive method of teaching which is at the heart of the museum results in the illusion that the museum is "learning the student" because the keepers of the temple are typically lurking behind the scene.

The

Boyce Thompson Southwestern Arboretum strives to be effective as a museum of living desert plants, making available appropriate materials for study by the public and by visiting scientists.

Newland

Sources of Seed

Sources of Arid Land Plant Seeds

Compiled by Kent C. Newland, Boyce Thompson

Southwestern Arboretum

Dieter Andreae

6111 Otzb erg- Tengfel d

Postfach

Heringer WE6

WEST GERMANY

(cactus seed)

Aztekakti

7892 La Grange

El Paso, Texas 79915

(Mexican cactus seed)

Burpee Seed Company

Riverside, Calif. 92502

(flower seed)

Christa's Cactus

529 W. Pima

Coolidge, Arizona 85228

(cactus seed)

Desert Emporium

P.O. Box 26

Warren, Michigan 48090

(cactus seed)

Green Horizons

500 Thompson Drive

Kerrville, Texas 78028

(Texas wildflowers, trees and shrubs)

Gebr. De Herdt

Bolksedijk 3E

B -2310

Rijkevorsel, BELGIUM

(cactus seed)

Karel Knize

P.O. Box 10248

Lima 1, PERU

(S.A. cactus seed)

J. L. Hudson, Seedsman

P.O. Box 1058

Redwood City, Calif. 94064

(worldwide seed)

Gerhard Kohres

Bahnstrasse 101

D -6106 Erzhausen/Darmstadt

WEST GERMANY

(cactus and succulent seed)

Hildegard Nase

2540 E. Ross Place

Tucson, Arizona 85716

(cactus seed)

Native Plants, Inc.

Seed Division Manager

400 Waukara Way

Salt Lake City, Utah 84108

(seed for reclamation, revegetation, forestry)

New Mexico Cactus Research

P.O. Box 787

Belen, New Mexico

(cactus and succulent seed)

Pan -American Seed

P.O. Box 438

West Chicago, Illinois 60185

(wholesale quantities)

231

Geo. W. Park Seed Co., Inc.

Greenwood, South Carol. 29547

(flower seed)

Theodore Payne Foundation

10459 Tuxford St.

Sun Valley, Calif. 91352

(California native plant seed)

Pecoff Bros. Nursery & Seed

Rt. 5, Box 215R

Escondido, Calif. 92025

(environmental restitution)

Jorg Pitz

St- Michael -Strasse 14

Kerpen -Buir

WEST GERMANY

(S.A. cactus seed)

Plants of the Southwest

The Railroad Yards

Santa Fe, New Mexico 87010

(wild trees, shrubs and flowers, SW states)

Clyde Robin

P.O. Box 2855

Castro Valley, CA 94546

(native plant seed from western North America)

Doug Rowland

200 Spring Road

Kempston, Bedford

ENGLAND MK42 8ND

(cactus and succulent seed)

Seeds of the World

P.O. Box 1037

East Nowra, NSW 2540

AUSTRALIA

( Austr. and worldwide seed)

Southwestern Native Seeds

P.O. Box 50503

Tucson, Arizona 85703

(native plant seeds)

Karlheinz Uhlig, Kakteen

D -7053 Kernen 1.R.

Lilienstrasse, 5

WEST GERMANY

(cactus seed)

Windethana Seed Service

Narrikup, W. AUSTRALIA 6326

(Austr. native plant seed)

232

Desert Plants 2(4)

Winter 1980 -81

Catastrophic Freezes in the Sonoran Desert

Janice E. Bowers

Office of Arid Lands Studies

University of Arizona

Introduction

Freezing weather plays an important role in the

Sonoran Desert. The effect of freezing on desert vegetation has been investigated by many workers, including Shreve (1910, 1911, 1912, 1914), Turnage and Hinckley (1938), Hastings and Turner (1965),

Felger and Lowe (1967) and Steenbergh and Lowe

(1976a, 1976b, 1977). The northern boundary of the

Sonoran Desert, defined by the northern extent of characteristic Sonoran Desert plants such as Saguaro

(Cereus giganteus), Triangle -Leaf Bursage (Ambrosia deltoidea), Canyon Ragweed (Ambrosia ambrosioides), Little -Leaf

Palo Verde (Cerdidium microphyllum) and Blue Palo Verde (Cercidium floridum), also coincides with the isotherm beyond which freezing temperatures have occurred which have lasted longer than 24 hours (Hastings, 1963).

Duration and intensity of freezing temperatures determine the northern and eastern extent of Sonoran

Desert vegetation (Shreve, 1914; Turnage and

Hinckley, 1938).

Saguaro populations at the eastern margin of the

Sonoran Desert have undergone demographic changes as a result of recurrent severe freezes between 1913 and 1971 (Steenbergh and Lowe, 1976a,

1976b, 1977). Steenbergh and Lowe conclude that severe freezes which kill large numbers of very young and very old individuals of Saguaro were not characteristic of the environment for 50 to 100 years before 1890. Catastrophic freezes damage or kill many other species as well, both at the margins of the Sonoran Desert and occasionally well into its center ( Turnage and Hinckley, 1938; Jones, 1979).

During the past 100 years, the climate of the

Southwest has become warmer and drier (Leopold,

1951; Hastings and Turner, 1965; Cooke and Reeves,

1976). Thus, subtropical plants in the Sonoran

Desert in Arizona must either adapt to more xeric conditions and to recurring catastrophic freezes or be eliminated by drought and frost. Although it might seem that catastrophic freezes should cause the boundaries of the Sonoran Desert to shift to the south and west, the general trend toward a warmer and drier climate tends to prevent higher- elevation species from moving downslope to occupy the vacated habitat. It is possible that the margins of the

Sonoran Desert have not dramatically shifted geographically, but that the composition and structure of plant associations at the margins have changed markedly due to the combined effects of catastrophic freezes and a more xeric climate.

Although many researchers have studied freezing in the Sonoran Desert, none have examined longterm weather data to determine the combined ef-

Bowers

Catastrophic Freezes 233 fects of freezing temperatures and duration of freezing on Sonoran Desert vegetation. This present paper will fill that gap by 1) defining catastrophic freezes in biological and climatological terms, and

2) correlating temperature records with observed catastrophic damage to Sonoran Desert plants during this century.

Methods

Since Steenbergh and Lowe (1976a) have stated that temperatures below 21 °F are critical to survival of Saguaro, I tallied the number of nights since 1894 when temperatures at the University of Arizona weather station in Tucson fell below 21 °F. In addition, I compiled hourly temperature data from

Tucson International Airport for winters between

1946 and 1979. [The hourly observations include data from January, 1946 to February, 1949; December, 1952 to December 1957; January, 1962 to

January, 1979. Temperature observations were made at 3 -hour intervals from January, 1965 to

January, 1979.] I also searched the literature for references to catastrophic freezes and frost damage to

Sonoran Desert plants. These references were compiled into a chronology of catastrophic freezes in the

Sonoran Desert (Appendix 1).

Results and Discussion

Winter temperatures fell below 21 °F in Tucson 86 times between 1894 and 1979. Catastrophic freezes in which a wide variety of native plants over large areas of Sonoran Desert were killed or severely damaged were less frequent, only nine such freezes occurring between 1894 and 1979 (Appendix 1). Apparently, although freezing temperatures below 21 °F kill juvenile and very old individuals of Saguaro (and possibly other Sonoran Desert plant seedlings as well), more severe conditions are necessary for catastrophic damage to occur. The problem, then, is to define catastrophic freezes in climatologic terms by discovering the combinations of low temperature and duration of freezing which cause catastrophic damage to Sonoran Desert plants.

Hourly temperature observations for 325 nights show that temperatures below 33 °F at the Tucson

International Airport lasted no longer than 9 hours on 85% of the nights, for 10 -15 hours on 14% of the nights, and for 16 hours or longer on only 2% of the nights. Similarly, temperatures above 24 °F occurred much more frequently than temperatures below

24 °F. On 90% of freezing nights the minimum temperature was 25 °F or higher (Figure 1). Hourly temperature observations also demonstrate that minimum temperature is loosely associated with duration of freezing (Figure 2). Minimum temperatures of 28 °F to 32 °F are most frequently associated with a relatively short period of freezing (1 -9 consecutive hours) and minimum temperatures of 20 °F to 26 °F are more frequently associated with a longer period of freezing (12 -20 consecutive hours). The general pattern which emerges from these data is that most freezes in Tucson are brief and not very intense. The few freezes that are very cold also last longer.

Hourly temperature data correspond well with the biologically defined catastrophic freezes listed in

Appendix 1. In most cases catastrophic freezes occurred when the lowest temperatures and the longest durations of freezing coincided (Table 1). For example, a freeze lasting 11 hours and reaching a minimum temperature of 22 °F was recorded on February 4, 1955. This freeze was apparently not catastrophic. However, on January 11, 1962, a freeze with the same minimum temperature but lasting 19 hours was catastrophic. On January 17, 1949, freezing temperatures lasted for 15 hours, but the minimum at the airport never fell below 31 °F. A later freeze on January 6, 1971 also lasted for 15 hours, but the minimum temperature was 18 °F. The 1949 freeze was not catastrophic but the 1971 freeze was.

Table 1. Duration of some freezes at Tucson International

Airport, 1946 -1979. Data are from U.S. Weather Bureau,

Local Climatological Summaries, Tucson, Arizona.

Date

Jan. 28, 1948

Jan. 29, 1948

Jan. 4, 1949

Minimum

Temp.

( °F.)

26

26

17

Duration

(Hours

32 °F.)

14

13

20

Remarks

Catastrophic

(see Table 1)

Jan. 5, 1949

Jan. 17, 1949

Jan. 18, 1949

Jan. 30, 1949

Dec. 28, 1954

Feb. 4, 1955

Jan. 11, 1962

17

31

26

26

18

22

22

14

13

11

19

16

15

12

Catastrophic

(see Table 1)

Jan. 12, 1964

Jan. 4, 1971

19

18

12

18

Catastrophic

(see Table 1)

Jan. 5, 1971

Jan. 6, 1971

Jan. 7, 1971

Jan. 8, 1971

Jan. 9, 1971

Dec. 24, 1974

Dec. 8, 1978

19

17

20

20

26

19

20

12

12

18

18

15

15

12

Catastrophic

(see Table 1)

Dec. 9, 1978 23

15

234

Desert Plants 2(4) Winter 1980 -81

27

26

25

32

31

30

29

28

24

23-1.11

22

21

20 AM

19-111

181

17 -11

0 10 15

20

Number of Nights

Figure 1. Number of freezing nights at Tucson

International Airport, 1946 -1979. Data are from U.S.

Weather Bureau, Local Climatological Summaries,

Tucson, Arizona.

45

Other characteristics of these particular freezes are also worth nothing. First, the overnight freeze on

January 17, 1949 was preceded and followed by nights that were not unduly cold. On the other hand, the catastrophic freeze of January 6, 1971 occurred on one of four consecutive nights of very cold weather. This is characteristic of the catastrophic freezes. Secondly, minimum temperatures vary from place to place across rather small distances. During the catastrophic freeze of January 11 -12, 1962, the minimum temperature both nights was 22 °F at

Tucson International Airport, 7 miles south of the

University of Arizona. At the University, the minimum was 24 °F on January 11 and 20 °F on January

12. The minimum temperatures were 20 °F and

15 °F on January 11 and 12, respectively, at the

Campbell Avenue Farm, only 4 miles north of the

University of Arizona.

50 55 60

Catastrophic freezes usually occur within 17 days of the winter solstice. Since there are more hours of potentially freezing darkness and fewer hours of relatively warm daylight during this winter solstice period, it seems likely that cold fronts moving into the Sonoran Desert on or about December 21 will be harsher than they would be in early December or late February. The longer nights mean that cold temperatures will be prolonged, occasionally with catastrophic results to native plants.

Summary

In the Sonoran Desert there is a gradient from mild freezes with little effect on native plants to severe freezes which inflict damage to frost sensitive plants (such as juvenile or very old individuals of Saguaro), to catastrophic freezes which kill or injure many species of plants over large areas.

65

Bowers Catastrophic Freezes

235

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

I Lowest recorded minimum

® Average minimum

ß 3 4

5 6 7 8

10

11

12

Number of Hours

13

14

Figure 2.

Correspondence of minimum temperatures with duration of freezing at Tucson International Airport,

1946 -1979. Data from source in Figure 1.

15 116 1

17 18

19 120

Severe freezes are less frequent than mild freezes and catastrophic freezes are less common yet. Catastrophic freezes have occurred more frequently during the last 100 years than in the previous century and may have modified the structure and species composition of plant associations on the margin of the Sonoran Desert. An analysis of hourly temperature observations shows that catastrophic freezes occur when low minimum temperatures and many consecutive hours of freezing interact. Between 1946 and 1979, there were four freezes which lasted between 15 and 20 hours, reached minimum temperatures between 17 °F and 22 °F, and caused widespread frost damage to Sonoran Desert plants. These were catastrophic freezes.

Appendix 1. A Chronology of Catastrophic Freezes in the Sonoran

Desert.

January, 1913. Minimum Temperature: 6 °F in Tucson, 16 °F in

Phoenix, 11 °F in Florence. Duration: 19 hours in Tucson; low temperatures "extended over a considerable portion of the night preceded by nearly 24 hours of continuous freezing weather."

Observations of Damage to Plants: "Thousands of small giant cactus plants growing near their greatest altitudinal limits were killed outright. Many other species also suffered great damage."

Source: Turnage and Hinckley, 1938; Thornber, 1916.

January, 1937. Minimum Temperature: 10 ° -20 °F in desert areas; 15 °F in Tucson, 20 °F in Altar, Sonora; 16 °F in Carbo,

Sonora; frost reported in Kino Bay, Sonora. Duration: 19 hours at

Tumamoc Hill in Tucson; in addition the 1937 cold wave

"lingered over an entire week." Observations of Damage to

Plants: Between Sells and Ajo, Olneya tesota, Celtis pallida,

Ambrosia ambrosioides, Jatropha cardiophylla, Encelia farinosa,

Sapium biloculare and Cereus thurberi were damaged. Branch tips of Cereus thurberi at Gunsight Pass in western Pima County were frozen back 8 -16 inches and lateral branches less than 12 inches long were completely killed. In southern Sonora, leaves and branches of Ficus petiolaris, Randia echinocarpa and

Pithecellobium dulce were damaged. Leaves and branches of

Guazuma ulmifolia and flowers of Ipomaea arborescens were damaged in central Sonora. Source: Tumage and Hinckley, 1938;

Wiggins, 1937.

January, 1949. Minimum Temperature: 16 °F at University of

Arizona at Tucson, 17 °F at Tucson International Airport. Duration: 20 hours at Tucson International Airport. Observations of

236

Desert Plants 2(4) Winter 1980 -81

Damage to Plants: "This is the second coldest January that the state has experienced in its 55 years of climatic history ... A damaging freeze on the 4th, 5th and 6th resulted in heavy losses to fruits and vegetables in the southern part of the state. " Source:

U.S. Weather Bureau, 1949.

January, 1962. Minimum Temperature: 14 °F at Organ Pipe Cactus National Monument, 20°F at Tucson International Airport.

Duration: "Freezing temperatures continued after the first night through the next day and into the second night" on the south slope of the Santa Catalina Mountains between 2500 and 4500 feet. Observations of Damage to Plants: 35% to 75% of the individuals of Saguaro in various stands on the south slope of the

Catalinas were killed. Mortality in Barrel Cactus in the same area was also high. Damage was also reported to Cereus thurberi, C.

schottii, C. giganteus, Bursera microphylla and other cacti and sub - tropical shrubs at Organ Pipe Cactus National Monument.

Source: Niering et al., 1963; Lowe, 1964; Steenbergh and Lowe,

1976b.

January, 1971. Minimum Temperature: 11 °F at Campbell

Avenue Farm in Tucson, 20 °F at Tucson International Airport.

Duration: 18 hours at Tucson International Airport. Observvtions of Damage to Plants: High mortality of seedling and juvenile Saguaros was observed in Saguaro National Monument

East, and Cercidium microphyllum and Ferocactus wislizenii were killed. Die -back and complete kill of Olneya tesota was seen in the Tucson Mountains. At Organ Pipe Cactus National

Monument, both Cereus thurberi and C. schottii were damaged and "a substantial number of individuals" were killed. Near

Guaymas, Sonora Ficus palmera was injured. Both Ipomaea arborescens and Lysiloma watsoni suffered leaf and twig damage in the vicinity of Hermosillo, Sonora. Source: Steenbergh and Lowe,

1976a, 1977; Jones, 1979.

December, 1978. Minimum Temperature: 15 °F at Campbell

Avenue Farm in Tucson, 21 °F at Arizona- Sonora Desert Museum,

21 °F at Organ Pipe Cactus National Monument. Duration: 18 hours at Tucson International Airport. Observations of Damage to Plants: The following species were frozen to the ground at the

Arizona- Sonora Desert Museum: Hyptis emoryi, Tecoma stans,

Beloperone californica, Ambrosia ambrosioides, Bursera microphylla. At Organ Pipe Cactus National Monument Jatropha cinera,

J. cardiophylla, J. cuneata, Bursera microphylla and

Encelia farinosa were frozen to the ground. Olneya tesota,

Coursetia microphylla, Beloperone californica and Sapium biloculare were damaged. Encelia farinosa and Lysiloma watsoni were severely damaged in Palm Canyon near

Magdalena, Sonora. Bursera fragilis, Cereus thurberi and

Erythrina flabelliformis were also damaged. Source: Anonymous,

1979; Jones, 1979; personal observation.

Literature Cited

Anonymous. 1979. The severe freeze of 1978 -79 in the

Southwestern United States. Desert Plants 1: 37 -39.

Cooke, R. U. and R. W. Reeves. 1976. Arroyos and Environmental Change in the American Southwest.

Clarendon Press. Oxford.

Felger, R. S. and C. H. Lowe. 1967. Clinal variation in the surface -volume relationships of the columnar cactus

Lophocereus schottii in northwestern Mexico. Ecology

48: 530 -536.

Hastings, J. R. 1963. Historical Change in the Vegetation of a Desert Region. Ph.D. Dissertation. University of

Arizona. Tucson.

Hastings, J. R. and R. M. Turner. 1965. The Changing Mile.

University of Arizona Press. Tucson.

Jones, W. 1979. Effects of the 1978 freeze on native plants of Sonora, Mexico. Desert Plants 1:33 -36.

Leopold, L. B. 1951. Rainfall frequency: an aspect of climatic variation. Transact. Amer. Geophys. Union

32: 347 -35 7.

Lowe, C. H. 1964. Arizona's Natural Environment. University of Arizona Press. Tucson.

Niering, W. A., R. H. Whittaker and C. H. Lowe. 1963. The

Saguaro: a population in relation to environment.

Science 142: 15 -23.

Shreve, F. 1910. The rate of establishment of giant cactus.

Plant World 13: 235 -240.

Shreve, F.

1911. The influence of low temperatures on the distribution of the giant cactus. Plant World 14:

136 -146.

Shreve, F.

1912. Cold air drainage. Plant World 15:

110 -115.

Shreve, F.

1914. The role of winter temperatures in determining the distribution of plants. Amer. J. Bot.

1:

194 -202.

Steenbergh, W. F. and C. H. Lowe. 1976a. Ecology of the

Saguaro: I. The role of freezing weather in a warm desert population. pp. 49 -92, in Research in the Parks.

National Park Service Symp. Ser. 1. Government Print ing Office. Washington, D.C.

Steenbergh, W. F. and C. H. Lowe, 1976b. The Saguaro giant cactus: an ecological perspective. pp. 71 -78, in

Proceedings of the First Conference on Scientific Research in the National Parks. Vol. I. National Park Service Transactions and Proceedings Series No. 5.

Steenbergh, W. E. and C. H. Lowe. 1977. Ecology of the

Saguaro: II. Reproduction, Germination, Establishment and Survival of the Young Plant. National Park

Service Scientific Monograph Series No. 8. Government Printing Office. Washington, D.C.

Thornber, J. J. 1916. Introduction. pp. 119 -122, in J. C. T.

Uphof. Cold Resistance in Spineless Cacti. University of Arizona Agricultural Experiment Station Bulletin

No. 79.

Turnage, W. V. and A. K. Hinckley. 1938. Freezing weather in relation to plant distribution in the Sonoran Desert.

Ecol. Monogr. 8: 530 -550.

U.S. Weather Bureau. 1894 -1979. Climatological Data

Summaries, Arizona.

Wiggins, I. L. 1937. Effects of the January freeze upon the

Pitahaya in Arizona. Ca ct. & Succ. Soc. J. 8: 171.

237

Yatskievych

Ferns of Huachuca Mountains

Ferns and Fern Allies of the Garden Canyon

Area of the Huachuca

Mountains, Cochise

County, Arizona'

George Yatskievych

Department of Plant Sciences

University of Arizona

.

'The author wishes to thank Dr. Charles T. Mason, Jr. for much help and many suggestions during the course of this project.

Introduction

The Pteridophytes of southeastern Arizona are an interesting and diverse group of plants that have received little study in the recent past. Although several botanists have made collections in this area, beginning with J. G. Lemmon in the 1880s, there are few publications describing the Pteridophytes there, and most of these are outdated. The species are, however, all included in Morton's treatment of

Pteridophytes in Arizona Flora by Kearney and

Peebles (1960). Ferriss (1909) published a nontechnical article on fern species that might be found in

Cochise County. Goodding (1912) published a short article describing some species of ferns from the area. Phillips (1945, 1946) published some notes on Arizona ferns and (1946a, 1947) a checklist of

Arizona ferns. The Arizona Game and Fish Commission surveyed some of the plants, including

Pteridophytes, of the Fort Huachuca Military

Reservation in Cochise County, as part of a

Wildlife Area Investigation (1949 -1951). More recently, Reeves (1976) included the Pteridophytes in a flora of the Chiricahua National Monument.

The purpose of this present project was to survey the ferns and fern allies occurring in Garden

Canyon, a rich canyon area of the Huachuca Mountains in southeastern Arizona, to ascertain which species were growing there and to provide information on the habitats and distributions of these plants.

The Area

Garden Canyon and its tributaries are located on the northeastern side of the Huachuca Mountains, in Cochise County. The area has received little attention in the past 25 years because it is located on the Fort Huachuca Military Installation. It includes what J. G. Lemmon called Tanner Canyon, the source of many of his Huachuca Mountain collections.

Garden Canyon is an open canyon about 41/3 miles long that drains toward the northeast. The elevational change is from 5100 feet to 7750 feet. There are 3 major vegetation zones in the canyon. At the mouth is a desert -grassland zone, with scattered

Agave, Mesquite (Prosopis), Cholla (Opuntia) and

Prickly Pear (Opuntia) in a flat, dry, grassy area.

This quickly grades into an Oak/Manzanita zone that might best be termed a Chaparral. The zone is characterized by dense stands of mixed shrubs, predominantly Scrub Oak (Quercus) and Manzanita

(Arctostaphylos) with occasional cacti and larger

Juniperus. Finally, toward the upper end of the canyon, there is a gradual transition to a conifer forest, with Pinus and Douglas Fir (Pseudotsuga)

238

Desert Plants 2(4) Winter 1980 -81 the dominant vegetation. This zone occurs as low as 5900 feet. A stream that is intermittent with perennial flow in some areas is found throughout the canyon bottom.

The study area also included the 3 primary tributary canyons of Garden Canyon. The uppermost of these is Sawmill Canyon, which branches toward the southeast near the upper end of Garden Canyon.

This tributary canyon is about 21/4 miles long, with an elevational change from 5900 feet to well over

7750 feet. It is characterized by many open, barren outcroppings of dolomitic limestone, on which few plants grow. The predominant vegetation zone is the conifer forest but there are many scattered patches of Chaparral. A perennial spring is located about 3/4 mile from the canyon mouth.

Also in the upper half of Garden Canyon, is

Scheelite Canyon, which branches toward the southeast and is about 21/4 miles long. Its elevation is

5800 -7250 feet, with a box at the upper end. This narrow, rocky canyon is walled by high cliffs, making it a very sheltered habitat. An intermittent stream runs in the canyon bottom. The third major tributary of Garden Canyon is McClure Canyon, which branches toward the northwest at 5500 feet.

This tributary is about 21/2 miles long and climbs to the ridge at 6750 feet. It is one of the wettest areas in the Huachuca Mountains, with a large series of perennial springs and a perennial stream in the upper half. The rest of the canyon is dry Chaparral, however.

The Garden Canyon area is rich in Pteridophytes because it contains many different exposures in a variety of habitats. Of particular importance are the smaller isolated habitats that are scattered through the canyon system. These account for the limited distributions of some species as well as the

Pteridophyte diversity. One of the commonest isolated habitats is that of the limestone cliff which occurs below the ridge in several areas throughout the canyon system. The limestone substrate seems to allow good seepage and the craggy nature offers both good protection and good anchorage for the plants. Greater numbers of plants were found on cliffs with a northern exposure than on comparable sites with other exposures.

Another common smaller habitat is that of the steep and very dry rocky hillside. This occurs in a few locations in Garden Canyon and lower McClure

Canyon. The most xerophytic of the Pteridophytes of the study area grow in this exposed habitat. Such plants are usually dormant, with brown, curled, dry fronds during the drier portions of the year.

The Pteridophytes are generally found growing from under the larger rocks; they seldom grow in open soil.

A third major isolated habitat is that of the riparian zone which occurs in the canyon bottoms throughout the Garden Canyon area. It is restricted to the areas immediately bordering the streams, except in upper McClure Canyon where there are large riparian groves. The dominant riparian vegetation is Cottonwood (Populus), Sycamore (Platanus),

Walnut (juglans) and Maple (Acer), with a dense, varied understory. The Pteridophytes that occur in this habitat are confined to the areas where the stream flow is perennial. They are becoming more widely distributed as the water re- routing by the

U.S. Army brings more water to the surface.

Methods

For this study, the Garden Canyon area was roughly divided into 15 sections. Each section was examined several times. The bulk of the field work was accomplished from January to July of 1978, with periodic trips afterward to verify some of the findings. Each section was thoroughly searched and all likely habitats for Pteridophytes were examined.

The survey area extended from the canyon bottom to the nearest ridge on each side and included all tributaries and ravines. The only exception to this procedure was in upper Sawmill Canyon, where the survey ended at the Fort Huachuca boundary fence, about 100 feet (in elevation) below the ridge.

Collections were made of each species found.

Voucher specimens were deposited at the University of Arizona Herbarium (ARIZ) and at the field herbarium of the Fort Huachuca Game Management

Office. Specimens were identified using Arizona

Flora by Kearney and Peebles (1960), and where necessary the names were brought up to date.

Specimens were examined at the University of

Arizona Herbarium, particularly the numerous

Huachuca Mountain collections of Goodding, in order to pinpoint the locations of some of the less common species in the canyon system.

Results

During the course of the survey 33 different

Pteridophytes were collected, comprising 13 genera and 32 species. One additional species was found during the herbarium search, which could not be located in the field. The genera and species in the

Cheilanthes fendleri.

Notholaena sinuata.

240

Desert Plants 2(4) Winter 1980 -81 following list have been alphabetized to facilitate species location.

SELAGINELLACEAE

Selaginella underwoodii Hieron var. dolichotricha

Weatherby. Found at only one location in the study area, but locally common there. This spikemoss grows at 6700 feet, on rock faces at the upper end of a steep ravine, located at the head of a small side canyon that branches southward near the mouth of Garden Canyon. This ravine was found to be especially rich in Pteridophyte diversity, harboring 6 species of ferns and fern allies uncommon in the Garden Canyon system. The ravine is moist with seepage year -round and is relatively sheltered by the surrounding cliffs. The substrate is mainly limestone, with several large granitic outcroppings. The topography is such that a series of ledges is formed in the middle.

EQUISETACEAE

Equisetum hiemale L. var. affine (Engelm.) A. A. Eaton.

Found growing semi -aquatically in sandy soil in riparian areas where the stream flow is perennial. This species occurs throughout Garden Canyon, above 5400 feet, in scattered colonies. A large stand is also located in a marshy area, in mucky soil, at McClure Springs.

Equisetum laevigatum A. Braun. Collected at the same locations in Garden Canyon as the previous species, but absent in McClure Canyon. Where the 2 species grow together, this is invariably the more abundant one. It also seems to form more extensive colonies than E. hiemale, with the plants growing further from the surface of the water. The hybrid between E. hiemale and E. laevigatum

(E. Xferrissii Clute), common elsewhere in southern

Arizona, was not found in the Garden Canyon system.

POLYPODIACEAE

Adiantum capillus- veneris L. Limited to one location in the Garden Canyon area. This species was found only in the vicinity of McClure Springs, at 6250 feet. It grows on elevated stream banks below the springs and on moist cliff overhangs, in mucky soil. It is also confined to relatively shady locations. The fronds seem to die back every winter.

Asplenium exiguum Bedd. Included in the survey on the basis of a single specimen (Goodding 142 -52, ARIZ). The label on this sheet reads "Steep side canyon; Garden

Canyon, Huachuca Mountains." The collection date is

December 26, 1952. No plants of this species were seen in the Garden Canyon system during this survey.

Asplenium monanthes L. Uncommon in the study area.

A few plants were found in a very sheltered rock crevice, with mosses, at 6600 feet in the same ravine described earlier for Selaginella underwoodii.

Asplenium resiliens Kunze. Collected in moist areas, in and around Scheelite Canyon, between 5800 and 7000 feet. This species grows from cracks in rocks and on limestone cliff faces, near streams and seepage areas. It is fairly common in protected areas of the Scheelite Canyon stream bed, but its range does not extend to the box at the head of the canyon, probably because the wet areas become more localized and less permanent as the canyon widens into the box.

Boomeria hispida (Mett.) Underw. One of the commoner ferns in the Garden Canyon area, below 6000 feet.

It is abundant under shrubs in the Chaparral habitat, but may also be found on partially shaded rock ledges.

Cheilanthes alabamensis (Buckl.) Kunze. Restricted to moist, rocky situations. A small colony of this fern was found near the mouth of Scheelite Canyon, at the 6000 foot level, where it was growing in the canyon bottom with Asplenium resiliens.

Cheilanthes eatoni Baker. A common fern of rocky situations, throughout the Garden Canyon area. It grows abundantly in moister situations, and is replaced on the driest, most exposed cliffs by Cheilanthes lindheimeri.

Forma castanea (Maxon) Correll is much more abundant than f. eatoni, which grows in scattered locations, throughout the range.

Cheilanthes feei Moore. Widely distributed in the survey area, but nowhere abundant. This fern is restricted to the limestone cliff habitat, growing from cracks in the cliffs, and is less common in exposed situations.

Cheilanthes fendleri Hook. Abundant in the Chaparral habitat, often growing with Boomeria hispida and

Cheilanthes wootoni. It grows from under rocks, and in rocky soil, often shaded by trees and shrubs.

Cheilanthes lendigera (Cay.) Swartz. Restricted to a single location in the survey area. A colony of this species was found growing at the 6500 foot level in the same steep ravine described earlier for Selaginella underwoodii and

Asplenium monanthes. It was locally common there.

Cheilanthes lindheimeri Hook. Found in several habitats, throughout the survey area. It grows in large patches in the Chaparral habitat, and from exposed cliff faces. It is one of the most xerophytic of the area

Pteridophytes, and may even be found growing from under rocks on the exposed, dry, rocky hillsides.

Cheilanthes villosa Davenp. Uncommon in the Garden

Canyon area. This species was found on a south -facing, dry, steep, rocky hillside, at 5900 feet, across from the mouth of Scheelite Canyon, in Garden Canyon. It also occurs in this habitat below 6000 feet at a few other locations in Garden Canyon.

Cheilanthes wootoni Maxon. Abundant in the Chaparral habitat, usually growing with Boomeria hispida and

Cheilanthes fendleri.

Cheilanthes wrightii Hook. Restricted to one locality in the survey area. A small colony of this species was found growing on a rocky slope near the canyon bottom, in lower Garden Canyon, at 5300 feet. The fronds of this small xerophyte dry up and become inconspicuous fairly early in the year and it is possible that the species is more widely distributed in the survey area than the collections indicate.

Cyrtomium auriculatum ( Underw.) Morton. _

"Phanerophlebia auriculata Underw." Restricted to a

Yatskievych Ferns of Huachuca Mountains

241 single location in the survey area. A colony of this species was found at the same location earlier described for

Selaginella underwoodii. The plants grow in moist soil with the rhizomes deeply recessed at the base of an overhanging terrace.

Cystopteris fragilis (L.) Bernh. var. tenuifolia (Clute)

Brown. Abundant in Sawmill Canyon, above 7200 feet.

This species grows in moist, loamy soil, under conifers.

The deciduous fronds do not appear until late May.

Notholaena aschenborniana Klotzsch. Restricted to one locality in the survey area. A colony of this species was found on the south -facing, dry, steep, rocky hillside in

Garden Canyon, across from the mouth of Scheelite

Canyon, between 5800 and 5900 feet. Some of the plants were growing with Cheilanthes villosa.

Notholaena aurea (Poir.) Desv. Found at the mouth of

Garden Canyon, under trees and shrubs near the edge of the Chaparral zone. This species inhabits the opener sections of the Oak/Manzanita habitat and was also found on an open hillside in middle McClure Canyon. It grows below the 6000 foot level.

Notholaena cochisensis Goodding. A common inhabitant of the steep, dry, rocky, exposed hillsides, throughout the Garden Canyon area.

Notholaena grayi Davenp. Restricted to steep, dry, rocky, exposed hillsides below 5700 feet. This species was found in both lower Garden Canyon and lower McClure

Canyon.

Notholaena integerrima Hook. Uncommon on steep, dry, rocky, exposed hillsides throughout Garden Canyon.

This species is much less common than related species

N. sinuata and N. cochisensis and is less widely distributed. It is more frequent in the upper half of Garden

Canyon than the lower half, but is nowhere abundant.

Notholaena limitanea Maxon var. limitanea. Found throughout the Garden Canyon area, but nowhere abundant. This species is found in moist situations, growing from under rocks or from cracks in cliff faces. It is most common in shady areas, adjoining the riparian zone.

Notholaena sinuata (Lag.) Kaulf. A common inhabitant of the steep, dry, rocky, exposed hillsides, throughout the

Garden Canyon area.

Pellaea atropurpurea (L.) Link. Frequent in moist, rocky situations, throughout the survey area. This species is frequently found growing with Notholaena limitanea, but is more abundant.

Pellaea intermedia Mett. Found on steep, dry, exposed, rocky hillsides and cliffs below 6500 feet, in Garden

Canyon and McClure Canyon. This species is not very abundant in the survey area.

Pellaea ternifolia (Cay.) Link var. wrightiana (Hook.) A.

F. Tryon. = " Pellaea wrightiana" Hook. Abundant throughout the survey area. This species was found in every habitat in the Garden Canyon area, except on the most exposed cliffs. It was less common in very moist, riparian situations. The individual plants were widely scattered.

Pityrogramma triangularis ( Kaulf.) Maxon var. maxonii

Weatherby. Restricted to one location in the survey area.

This species was found in a dense colony in the micro habitat created by the sheltering over -hang of a large boulder, just below the ravine described earlier for Selaginella underwoodii and Asplenium monanthes. The pocket was densely shaded and the plants were growing in very moist, fine, sticky soil. This is the first published report of

Pityrogramma triangularis var. maxonii from Cochise

County, although this population was previously collected from by Goodding (163 -50, 139 -52, 11 -53) in

1950 -1953.

Polypodium thyssanolepis Klotzsch. Restricted to very sheltered, moist situations. This species was found in two locations in the survey area, growing in overhanging limestone cliff areas. The first was in the ravine previously discussed for Cheilanthes lendigera and Selaginella underwoodii. The second was in a short series of cliffs just above the canyon bottom, in lower Garden Canyon, in the r4parian zone, at 5300 feet.

Woodsia mexicana Fee. Widely distributed in Garden

Canyon, below 6500 feet. This species occurs in moist, rocky areas, and on moist limestone cliffs. It is able to grow in fairly exposed situations, and the deciduous fronds appear as early as March.

Woodsia plummerae Lemmon. Widely distributed between 5300 and 7750 feet in Garden and Sawmill

Canyons. This plant is found in the habitat previously described for Woodsia mexicana, as well as growing with Cystopteris fragilis, in moist soil under trees in the confier forest. It also has deciduous fronds that appear as early as March.

Literature Cited

Arizona Game and Fish Commission, Wildlife Restoration Division. 1949 -1951. Fort Huachuca Wildlife Area

Investigations -Job Completion Reports of the

Charles T. Vorhies Game Habitat Research Project.

pp. 1 -28.

Ferriss, J. H. 1909. Ferns of Cochise County, Arizona. Fern

Bull. 17: 1 -7.

Goodding, L. N. 1912. New Southwestern ferns. Muhlenbergia 8: 92 -94.

Kearney, T. H., R. H. Peebles and Collaborators. 1960.

Arizona Flora. 2nd ed. University of California Press.

Berkeley. pp. 27 -49.

Phillips. W. S. 1945. Some notes on Arizona ferns. Amer.

Fern Journ. 35: 58 -60.

Phillips, W. S. 1946. Additional notes on Arizona ferns.

Amer. Fern bourn. 36: 58 -60.

Phillips, W. S. 1946a. A checklist of the ferns of Arizona.

Amer. Fern bourn. 36: 97 -108.

Phillips, W. S. 1947. A checklist of the ferns of Arizona, cont. Amer. Fern bourn. 37:13 -20, 39 -51.

Reeves, T. 1976. Vegetation and Flora of Chiricahua National Monument, Cochise County, Arizona. MS thesis. Arizona State University. Tempe. pp. 99 -102.

Cheilanthes lindheimeri.

Cheilanthes eatoni.

Ya tskievych Ferns of Huachuca Mountains

243

Notholaena limitanea (upper) with Cheilanthes lindheimeri.

244 Desert Plants 2(4)

Winter 1980 -81

Reviews

"

Plants of Deep Canyon and the

Central Coachella Valley, California

Jan G. Zabriskie. Drawings by Carol Lewis. Philip L. Boyd

Deep Canyon Desert Research Center, University of

California, Riverside. 1979. 175 pp.

The author intended the book not only for scientists interested in desert research, but also "the expanding audience of people interested in native desert plants as they occur in their natural environment."

A habitat map in color folds out at page 13, followed by a series of nine chapters, each presenting a sketch of the vegetation of one of the habitats. Rather than presenting a standard floristic list, the author has reported the species in tabular form, graphing the elevational range of each.

This has an obvious visual advantage or graphic impact which allows the elevational ranges of different species to be more easily compared. It has the disadvantage, however, of leaving no room for helpful annotations and species discussions. Such information is presumably reported in the chapters dealing with vegetation by habitat.

This would probably be disconcerting only to a traditional plant taxonomist accustomed to scanning through annotated taxonomic treatments for observations on a certain family or genus being researched. Noteworthy observations scattered through the text can presumably be located by using the index.

A final chapter presents ecological data (principally percent cover and species diversity) from surveys made at

122 -meter elevational intervals along a transect. Charts are presented which compare percent cover of specialized plant life forms to total plant cover in major habitats. Percent evergreen cover relative to total plant cover appears to be bimodal, being particularly low between 488 and 732 meters on rocky slopes. Presumably these sites had little of the Creosotebush (Larrea tridentata) of lower elevations and little of the Pinyon (Pinus monophylla) and

Chaparral vegetation of slightly higher elevations.

Another bimodal distribution appears in the chart which displays percent winter -deciduous cover relative to total plant cover. This bimodality must come from the phenomenon of cold air drainage at the intermediate elevations, cold -tolerant Mesquite (Prosopis glandulosa var.

torreyana) being present on the valley floor and other cold -tolerant winter -deciduous species on the high montane slopes.

Percent succulent cover relative to total plant cover is high in just those elevations where winter -deciduous cover is low, again suggesting a response to cold air drainage. On rocky slopes at 732 meters elevation, succulents provide over 40% of the plant cover. Percent drought

deciduous cover relative to total plant cover, clearly an indicator of aridity, is virtually nil on the valley floor, suggesting the presence of water, high from 122 to 1,100 meters, and very low or zero at higher elevations, in classical test -book fashion.

Dry Lands: Man and Plants.

Robert Adams, Marina Adams, Alan Willens and Ann

Willens. The Architectural Press Ltd. London, England.

1978. vii + 152 pp. Price, 15.00 British Pounds.

On thumbing through this book it appears to be a scholarly review. Upon closer examination, the book attempts to cover so many topics in so small a space that it falls into the bad habit of oversimplifying. Under "DESERT VEGE-

TATION TYPES" it recognizes 1) ephemeral plants, 2) succulent perennial plants, and 3) woody perennial plants, said to be mutually exclusive categories. But nothing is said of the herbaceous (i.e. nonwoody) perennials or the annuals which are not ephemeral or only facultatively so.

Succulent perennials are said to be either spiny like the

Cactaceae or "non -spiny but physiologically swollen plants." For a plant scientist to conjure up an image of a

"physiologically swollen plant" he must imagine some pathological condition resulting from a plant being thrust into some powerful solution of unbelievable osmotic concentration. The first part of the statement concerning the spiny or non -spiny nature of succulents is like saying that a plant either has stiff branches, or if it doesn't, then it has green leaves. Of what relevance, you ask the author. Such statements disincline a botanist to spend much time in seriously reading the book. In the same paragraph, the ability of succculents to close their stomata in the daytime and open them at night is said to be a phenomenon which "is being intensively researched, especially in the

U.S.A." And here in Arizona, we thought that this had been thoroughly reported on by scientists at Tumamoc

Hill in Tucson well over 50 years ago.

Important Notices

Subscriptions to Desert Plants

To obtain a one -year subscription to

Desert Plants, just send $10 to the address below

Desert Plants

Boyce Thompson SW Arboretum

P.O. Box AB

Superior, Arizona 85273

Make sure you provide your current address with zip code. If the subscription is a renewal, please say so to avoid receiving two copies of the same issue.

In the case of gift subscriptions, we will send a letter to the recipient telling who is sending the gift, if this is requested. Of course, no extra charge.

M AVA!t7M^ 3h.VtIämartt:sP'.

Fifth Annual Arboretum Plant Sale

Dates

April4 -5, 1981

(Saturday and Sunday)

Location

Boyce Thompson Southwestern Arboretum

U.S. Highway 60, 3 miles west of Superior,

Arizona

(60 miles east of Phoenix; 100 miles north of Tucson)

Remember

We recommend that you attend the plant sales that our sister institutions have as well.

March 28 -29, 1981

Plant Sale at Désert Botanical Garden,

Phoenix

April 11 -12, 1981

Plant Sale at Arizona -Sonora Desert

Museum, near Tucson

245

Jimson Weed, Tolguacha, or Thorn Apple (Datura meteloides) photographed at the old Silver King Mine near the Arboretum by Leslie Ely.

The Story of Jimson Weed. Species of Datura grow on sites which are open, disturbed, sunny and often arid.

Cowboys, desert dwellers or denizens of "waste places" often refer to the plants by the name Jimson Weed. This is in reality a contraction for "Jamestown Weed" (Datura stramonium), a plant which became infamous in colonial

Virginia. In 1870 J.

E. Dodge reported that "Datura meteloides grows abundantly in Arizona" and that "the

Mohave Indians gather the leaves and roots, bruise and mix them with water." After being allowed to stand for several hours, "the liquid is drawn off. It is a highly narcotic drink, producing a stupefying effect." The California

Indians "use a decoction of this species to stimulate young females in dancing." The Pah -Utes "... ferment in the sun a watery infusion of the bruised seeds, and drink the liquor for the purpose of intoxication." Pharmacologists Edward

P. Claus and Vano E. Tyler discussed D. stramonium in

1965, recording that early settlers near Jamestown in colonial Virginia "used it as a 'pot herb' with fatal results."

Charles F. Millspaugh in 1892 characterized the Jamestown plant as growing in waste places or garbage heaps and noted that "... the American Aborigines named it The

White Man's Plant ..." in allusion to its place of growth "... near the homes of the civilized." In 1922 L. H.

Bailey wrote that at the "first successful settlement in

America- Jamestown, Virginia, 1607 ..." the men ate

Datura "... with curious results. Capt. John Smith's account of their mad antics is very entertaining." The colonial historian Beverly (in History of Virginia, p. 121) recorded that soldiers sent to put down Bacon's Rebellion gathered the young sprouts and ate them as a pot herb,

"the effect of which was a very pleasant comedy, for they turned natural fools upon it for several days. One would blow up a feather in the air; another would dart straws at it with fury; another, stark naked, was sitting up in a corner like a monkey, grinning and making maws at them; a fourth would fondly kiss and paw his companions."

After eleven days they "... returned to themselves again, not remembering anything that had passed." Unfortunately many other records of Datura- eating list death as the end result. For example, in 1911 L. H. Pammell recorded a case where some boys "... imagined themselves Indians and roamed about and ate parts of various plants ..." including

Jimson Weed. "One died in a state of wild delirium; another was saved after heroic treatment ..." Pammell also recorded the poisoning of five children who had eaten

Datura growing in a garden "under the fanciful trade name of Night- blooming Cactus." Daturas have become spread as weeds throughout much of the world and several authors have stated that "Thugs" and "Assassins" in

India poisoned people with them in furtherance of their criminal activity.

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