Ironwood is one of the desert’s most beautiful trees, being particularly colorful when the new, dark-green leaves and violet, wisteria-like flowers give it a lavender glow in late May or early June. Since the tree survives only in warm locations, it has for years served as a guide to citrus growers in selecting sites for orange, lemon, or grapefruit plantings.
Foliage of the Ironwood is dense and evergreen, and the wood is very heavy and so hard that it cannot be worked with ordinary tools. When thoroughly dry, it makes high-quality firewood, and as a result it has been cut and removed over much of the desert, hence mature trees are becoming relatively scarce. Indians used the wood for arrow points and as tool handles.
Ironwood trees grow along desert washes, often in company with Mesquite and Paloverde. Blossoms are much more numerous in some years than in others. Although the trees, when in bloom, make a spectacular showing, they are very difficult to capture on color film, and photographs that do them justice are rare. Seeds, which mature late in the summer, are roasted and eaten by desert Indians who prize them for their peanut-like flavor. They are eaten also by various desert animals.
In Organ Pipe Cactus National Monument and in some other parts of the desert, Ironwood trees have become heavily infested with Mistletoe which stunts or kills the branches and produces grotesque, tumor-like swellings.
VIOLET
Since the Aster is one of the most widespread and best-known of the flowers, it is usually easily recognized. There are many species, principally perennials, ranging from low-growing, single-stemmed plants, sprawling, many-stemmed plants with large flowers, to tall bushes. Desert species are found on dry, rocky hillsides and along roadsides and on waste ground.
Aster tanacetifolius leaf shapes
Aster tanacetifolius leaf shapes
The Aster is by no means restricted to the desert. Over much of the United States they are considered as fall bloomers, but many species blossom in the spring while others are at their floral best in midsummer.
VIOLET
Widespread through the Southwest at nearly all elevations, the Penstemons are conspicuous herbs or small shrubs with showy flowers that attract attention and admiration when they are in bloom in the spring and early summer on the desert.
PURPLE
Lupines are among the old dependables of spring display flowers of the desert, usually mingling with other blossoming herbs to create the bright color pattern for which the desert is famous in early spring, but occasionally growing in pure stands. Ranging in color from pale pink to deep purple, the Lupines are usually considered as blue flowers.
The name “Lupine” comes from the Latin word meaning wolf and was applied to these plants because they were believed to rob the soil of its fertility. Actually, they prefer the poorer, sandy soils and, by fixing in the soil nitrogen that they, in common with other plants of the pea family, are able to obtain from the air, they actually improve the land on which they grow.
Perhaps the best known display of Lupines takes place each spring inTexas. Here the “Bluebonnet” (L. texensisandL. subcarnosus) has been named the state flower of Texas, and the annual spring display attracts thousands of people to the areas of heavy bloom. The majority of Lupines have handsome flowers, some species are fragrant, and several species are cultivated as ornamentals. The seeds of a few species contain alkaloids which are poisonous to livestock, especially sheep.
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This root parasite, although not common, is sufficiently strange and striking in appearance to arrest attention. Its purple to yellowish-brown, leafless flower stalks somewhat resembling coarse shoots of asparagus rise above the desert soil, usually in open, sandy locations.
Broomrape, of which there are several species, is found throughout the Southwest from southern Utah and Nevada to Texas, California, and Mexico.
The plant is parasitic on the roots of a number of different plants, but the desert species usually parasitize Burrobush, Bur-sage, and other composites. Flowers are small, purple with brown and white markings, and monopolize the plant stalk in the absence of foliage.
Underground parts of the plant were eaten by Southwestern Indians. The name “Cancer-root” refers to the reported efficacy of treatment in applying the stems of the plant to ulcers.
PURPLE
A very large genus of plants, with 78 species recorded in Arizona alone,Astragalusranges from the driest, hottest parts of the desert to high mountain peaks and the far north.A. nuttalianusis the commonest of the desert species and is found on dry plains, mesas, and slopes below 4,000 feet from Arkansas and Texas westward to California and south into Mexico.
Some of the species, of whichMollisimus(Wooly-loco) is one, contain a poisonous constituent causing the well-known and often fatal loco disease of livestock, particularly horses. (Loco is a Spanish word meaning “crazy.”) Other species which prefer soils rich in selenium take up enough of that toxic mineral to make them poisonous to livestock, especially sheep.
Nearly all of the species are colorful and spectacular when in blossom, and some of them have a rank, disagreeable odor.
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Quite showy when in flower, these common roadside plants attract considerable attention during the late spring and summer. Some species become troublesome in cultivated fields and are difficult to eradicate. An alkaloid, solanin, reported as present in the leaves and unripe fruits of several species, renders them poisonous. Pima Indians add the crushed berries ofS. elaeagnofoliumto milk in making cheese.
The yellow-floweredS. rostratumis heavily covered with spines, including both stems and fruit, giving it the name of Buffalobur. This species is said to be the original host of the now widespread pest, the Colorado Potato Beetle.
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Widely distributed on salty and alkaline soils throughout the warmer parts of the Western Hemisphere, there are several species and varieties of Wild-heliotrope. The flowers, which are almost white, shading to a pale purple in the corolla throat, open as the spike uncoils, perfuming the desert air with their fragrance. The name “Pusley” which is applied to this plant in some localities is possibly a corruption of “Purslane.”
Pima Indians are reported to powder the dried roots of these plants, applying the dust to wounds or sores. The name “Wild-heliotrope” is also applied to another desert flower,Phacelia crenulata(which see), causing no little confusion.
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Seldom found above 3,000 feet elevation, the rank-smelling Arrowweed forms dense, willow-like thickets in stream beds and in moist, saline soils. It is common in moist locations from Texas to southern Utah and south into California and Mexico; usually in pure, dense stands.
The green foliage gives off an agreeable odor, but when the plant dries this becomes rank and unpleasant, clinging to the plant long after it has been cut. This odor is often a characteristic of native dwellings where Arrowweed has been used as a ceiling mat above the rafters.
Arrowweed is browsed by deer, and sometimes by horses and cattle. The straight stems were used by Indians in making arrowshafts, and are still important as a construction material in the walls and roofs of mud huts. The stems are used, also, by desert Indians in basketmaking, and in fabricating storage bins and animal cages. From the foliage of the stem tips, Pima Indians brewed a tea which they used as an eye wash.
The flowers are reported to furnish considerable nectar gathered by Honeybees. The blossoms are inconspicuous and develop into tawny-tufted seed-heads.
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Disproportionately large flowers for the size of the low-growing, small-leafed plant make it particularly conspicuous in the open, sandy locations where it blossoms in the springtime.
Although the Monkeyflower is usually thought of as moisture-loving, there are a number of desert species. The flowers are quite easy to recognize, as they closely resemble the Monkeyflowers which grow in the moist places surrounding seeps and springs, and they also are somewhat similar in appearance to their close relatives the Snapdragons and Pentstemons.
The desert species are well worthy of consideration for cultivation as garden ornamentals.
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Although the plants are very small, they grow close together and the blossoms are often quite large in comparison. The reddish-purple color of the flowers stands out in sharp contrast to the green of spring vegetation so that a widespread growth of the plants forms patches or mats of colorful desert carpeting.
Masses of the plants are usually found on open flats, often among Creosotebush, and on either clay or sandy soils. In dry years, growth is restricted and a tiny plant may bear but a single flower, the blossom sometimes almost as large as the rest of the plant.
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A common roadside perennial, Spiderling becomes an annoying garden weed when it invades open fields and areas of cultivation. Its trailing stems and sticky foliage interfere with tillage. The flowers are small but numerous and grow in attractive, colorful clusters. This species is widely distributed, not only throughout the deserts of the Southwest, but also in tropical and subtropical America.
In addition toB. caribaea, other species ofBoerhaaviaare widespread throughout areas of the Southwest below 5,500 feet elevations. The plants usually grow where they are exposed to full sunlight, although sometimes found in open brushlands, and reach full flower in late summer and autumn months.
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This short, leafy annual ranging in color from rich velvet red to purple is noticeable even as an individual plant, but, following winters of above average rainfall, it often grows en masse, covering portions of the desert floor with a carpet of bright purple; sometimes in pure stands, often mixed with Goldpoppy, Lupine, and other spring flowers.
SinceEscobitais limited in range to southern and western Arizona, California, and Lower California at elevations below 3,000 feet, Organ Pipe Cactus National Monument is well within its range, and in that area can be seen at its spectacular best.
The California variety has the lower lip of the blossom tipped with rich yellow.
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Aside from the true Tree Cholla (Opuntia fulgida), which is the largest of the branching, cylindrical-jointed cacti and is very common in restricted portions of the desert in the Tucson-Phoenix area, the species listed above are the largest, most representative, and most widely spread of the Chollas (CHOH-yahs).
The bright red to purple flowers ofO. spinosiorandO. imbricatamake them particularly attractive during the blossoming season, while the extreme variability, from yellow to red and purple, of the flowers ofO. acanthocarpamake its identification by this means always a matter of uncertainty. Fruits ofspinosiorandimbricataare quite large, yellow, and at a distance may be mistaken for blossoms.
Flowers ofO. fulgidaare small, pink, and appear in midsummer followed by fruits which remain on the plant to form long hanging clusters relished by cattle. A hybrid betweenspinosiorandfulgidais reported along the Gila River west of Florence, Arizona.
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Sometimes called Bullthistles, these biennials or perennials with spiny stems, prickly leaves, and heavy flower heads ranging in color from white to purple need no introduction to most people.
The Mohave Thistle is the commonest form found in southern California, being abundant, sometimes in dense stands, in open gravelly valleys, on rocky slopes, or about alkaline seeps in the Mohave Desert. Range of the New Mexico Thistle extends westward to the eastern borders of the Mohave Desert.Cirsium californica, with white blossoms, occurs in Death Valley National Monument at elevations between 4,000 and 5,000 feet.
Navajo and Hopi Indians are reported to use the Thistle plant for medicinal purposes.
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Sandverbenas are attractive, low-growing herbs with pink-purple to lavender, fragrant flowers forming clusters or heads which cover the plants. Desert species are conspicuous in the springtime when they line roadsides and carpet open, sandy locations, such as dry streambeds, with a mass of purple. Although they are often found in solid patches, they frequently intermingle with other spring flowers such as the Bladderpod producing a gay pattern of color.
Other species are found at higher elevations and are common during the summer months.
Some of the desert species blossom a second time in September.
plant silhouette
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Growing in open clumps with stems resembling spine-covered cucumbers standing on end, the Hedgehog is the first cactus to blossom in the spring. Flowers vary considerably in color ranging from lavender through purple to a rich red.
Fruits (called “pitayas” in Texas) are dark mahogany red, juicy, rich in sugar, and may be eaten like strawberries, hence the name Strawberry Cactus. They form an important item in the diet of birds and rodents. Pima Indians consider them a delicacy.
A close relative, the Rainbow Cactus (Echinocereus rigidissimus) is restricted in its distribution to elevations between 4,000 and 6,000 feet. It is called “Rainbow” Cactus because of alternating bands of red and white spines encircling the stem and marking growth of different seasons and years. The blossoms of the Rainbow Cactus are pinkish (yellow in western Texas) and are large and showy in comparison with the small size of the single-stemmed plant.
PURPLE
Very common and abundant in early spring, the pale blue to violet flowers of this small, delicate perennial Lily are conspicuous on open slopes and mesas. Found below 5,000 feet from southwestern New Mexico to California and northward to Oregon, they are widely scattered over the desert areas of the Southwest. Pima and Papago Indians ate the small bulbs, as also did the early white settlers who named them Grassnuts.
BLUE
AlthoughE. arizonicusis considered one of the desert’s most beautiful wildflowers, members of the genus are by no means limited to the desert. They are found in sunny locations on desert grasslands, open plains and dry mesas below 5,000 feet from the Dakotas and Montana to Argentina.
The flowers, although rarely more than ½ inch in diameter, are bright azure or sky blue, and seem large in comparison with the small leaves and weak, spreading stems of the plant that bears them.
Although the genusIpomoeais the true Morningglory, blossoms ofEvolvusare similar in appearance, although flattened, hence are sometimes called Wild-morningglory.
BLUE
The word “Sage” is derived from the idea that these plants had the power to make a person wise or sage. Please do not confuse the Desert-sage with Sagebrush (Artemisia) which does not grow in low-elevation deserts but which, due to popular writings and “western” movies, is associated in the public mind with any brushy plant found in the west.
Seeds of the Chia at one time formed a staple article of diet among southwestern Indians, and are still used by natives in Mexico for food and for making mucilaginous poultices.
The flowers of several species of Chia are very ornamental and the plants are quite common, usually in sandy soil.
BLUE
Desert Larkspurs are low-growing, spring or early summer-flowering in habit, often occurring in colonies, and frequently intermingle with other spring flowers thereby adding their blue to the colorful tapestry of ground cover. They are readily recognized because of their resemblance to the cultivated varieties called Delphiniums, and because of the tubular extension or “spur.”D. amabileis the most drought-resistant of all southwestern species and may blossom in the desert as early as February.
Because they contain delphinine and other toxic alkaloids, Larkspurs are poisonous to livestock, particularly sheep. On the desert, the plants are small and bear few but beautiful blossoms. They prefer open, gravelly soil.
It is reported that the Hopi Indians grind Larkspur blossoms with corn to produce blue meal.
BLUE
Famous, although not common, throughout the frostless areas of the desert, the Smoketree, because of its gray-green, leafless, plume-like growth resembles at a distance a gray cloud of smoke hovering over a desert campfire. When in flower, in May or June, it is one of the handsomest of desert shrubs. It is always found in the bed of a sandy wash where it obtains moisture from runoff following summer showers or winter rains.
In California, it occurs in portions of both the Mohave and the Colorado Deserts, and in Arizona is restricted to the western part of the state. It is fairly abundant near Quitobaquito in the southwestern corner of Organ Pipe Cactus National Monument.
Other species of Indigobush, of which there are many, are less famous than the Smoketree, but all have purple or indigo flowers and most of them are beautiful and noticeable when in blossom. Indians used an extract from the twigs for dyeing basket material and ate the roots ofD. terminalis.
BLUE
Sturdy, conspicuous flower and seed heads together with the large leaves of these coarse, roadside plants, although hardly to be considered as beautiful, attract considerable attention and arouse the curiosity of the observer. Some species are garden weeds introduced from Europe. In the desert, the large, coarse leaves and pinkish flower stalks make quite a showing in sandy washes and along the roadsides as early as March and April. The plant is being considered as a source of tannin (from its tubers) to replace that formerly obtained from Chestnuts.
GREEN
Jojoba(hoh-HOH-bah) is another of the desert plants which is noticeable, not because of its flowers, but due to its leathery, gray-green foliage which persists throughout the year. These shrubs are numerous at elevations between 1,000 and 4,300 feet in the lower levels of desert mountain ranges, particularly on the alluvial fans at the mouths of canyons.
The acorn-like nuts, which taste something like filberts, but are bitter because of their tannin content, were long an important item of food among the Indians and the early settlers. The thickly set, evergreen leaves are browsed by Deer and other animals, and the nuts are gathered by Ground Squirrels.
The nuts contain an edible oil (actually a liquid wax) which has some medicinal value and is used in small quantities in the manufacture of hair oil. Attempts to raise the nut in commercial quantities have not proved successful. On occasions the nuts have been roasted and used as a substitute for coffee.
GREEN
Readily recognizable because of their milky sap and the pods filledwith silky-winged seeds, the Milkweeds are generally considered as poisonous to livestock, although rarely eaten. Appreciable quantities of rubber are found in the sap of some species.
GREEN
Two intricately branched, thorny shrubs with green bark and leaves reduced to small scales and otherwise resembling each other are both popularly known by the names of Crown-of-thorns and Crucifixion-thorn, although they are not closely related botanically.
Flowers of both are small and inconspicuous, although when the bushes are in full bloom, they are quite noticeable. Even so, it is the unusual and eye-arresting appearance of these shrubs which appear as leafless masses of robust thorns, making them a conspicuous feature of the desert and arousing the interest and curiosity of observers.
In some locations these shrubs are sufficiently abundant to form thickets which repel livestock. Fruits ofH. emoryiremain on the plant for years, and it is usually possible to identify each season’s fruit clusters by the degree of weathering. These masses of brown to black fruits are very noticeable and are often mistaken for parasitic growths or the results of a disease. A somewhat similar shrub, sometimes attaining tree size and superficially resembling the Paloverde (seep. 36), is the Mohave-thorn (Canotia holocantha). It is found at elevations between 2,500 and 4,500 feet, over much of southern and western Arizona and northern Sonora, and blossoms from May to August.
Noticeable because of its ashy foliage, Bur-sage is a low, rounded, white-barked shrub, the several species of which are very common on the dry plains and mesas up to 3,000 feet. The flowers are small, without petals, and colorless inasmuch as they are wind-pollenated and do not need to attract insects.
It is classed by A. A. Nichol as one of the major plants of the Paloverde-Bur-sage-Cacti plant association, one of the three plant communities of the Sonoran Desert.
Bur-sage is one of the favorite foods of burros and sheep, and is said to be preferred also by horses.
GREEN
Seepweed, which is usually an indicator of alkaline soil, is browsed to some extent by cattle when other feed is scarce. The young plants are used for greens by the Pimas and other desert Indians, sometimes eaten with cactus fruits.Pinolewas made by roasting the seeds. Coahuila Indians extracted from the plants a black dye which they used in art work.
Flowers of the Seepweed are small, greenish, and without petals. Since the pollen is carried by the wind, color to attract insects to the flowers is not necessary. Because of its tolerance for somewhat salty or alkaline soils, Seepweed thrives along the margins of dry lakes and on salt flats where moisture is near the surface. On the desert of southern California it is often associated with Mesquite and Quailbrush, the sooty-green to brown plants standing out in sharp contrast.
Because it is so common in moist locations throughout the Southwest, and sufficiently unusual in appearance to arouse curiosity as to its identity, Seepweed is included in this publication regardless of the fact that its flowers are small and inconspicuous.
GREEN
Benson, Lyman; andDarrow, Robert:A Manual of Southwestern Trees and Shrubs; University of Arizona, 1944.
Benson, Lyman:The Cacti of Arizona; University of Arizona, Second Edition, 1950.
Black, Homer:Common and Larger Plants Near the Cavern Entrance; Carlsbad Caverns National Park; mss. 1944.
Cooper, Norman C.:Check List of Plants of Organ Pipe Cactus National Monument; mss. 1942.
Jaeger, Edmund C.:Desert Wildflowers; Stanford University Press, Revised Edition, 1944.
Joint Committee on Horticultural Nomenclature:Standardized Plant Names; Second Edition, 1942.
Kearney, Thomas H.; andPeebles, Robert H.:Flowering Plants and Ferns of Arizona; Government Printing Office, 1942.
McDougall, W. B.:Vegetation of White Sands National Monument; mss. 1939.
McDougall, W. B.:Check List of the Plants of Death Valley National Monument; mimeo. 1945.
McDougall, W. B.; andSperry, Omer E.:Plants of Big Bend National Park; Government Printing Office, 1951.
Nichol, A. A.:The Natural Vegetation of Arizona; University of Arizona Technical Bulletin No. 68, 1937.
Shantz, H. L.; andPiemeisel, R. L.:Indicator Significance of the Natural Vegetation of the Southwestern Desert Region; Government Printing Office, 1925.
Sperry, Omer E.; andWarnock, Barton H.:Plants of Brewster County, Texas; Sul Ross State Teachers College Bulletin, Vol. 21, No. 1, Alpine, Texas, 1941.
Taylor, Walter P.;McDougall, Walter B.; andDavis, William B.:Preliminary Report of an Ecological Survey of Big Bend National Park; March-June, 1944; mimeo.
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