Astragalus mollissimus illustrated

Texas deserts. Blooms purple. April-May. Size: 4 to 12 inches high.

A very large genus of plants, with 78 species recorded in Arizona alone, Astragalus ranges from the driest, hottest parts of the desert to high mountain peaks and the far north. Astragalus nuttallianus is 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 which woolly loco (mollissimus) is one, contain selenium, 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.


Groundcherry, Wild Potato, Trompillo, Horsenettle

Arizona, Texas and California deserts. Blooms purple-violet. April-September.

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, solanine, reported as present in the leaves and unripe fruits of several species, renders them poisonous. Pima Indians add the crushed berries of Solanum elaeagnifolium to milk in making cheese.

The yellow-flowered Solanum rostratum (b) is 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.

Salt Heliotrope

Wild-Heliotrope, Quailplant, Chinese-Pusley

Arizona, California and Texas deserts. Blooms purple. March-April. Size: Spreading weak stems up to 18 inches.

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.

Arrowweed Pluchea

Arizona, California and Texas deserts. Blooms roseate purple. Spring. Size: Perennial, 3 to 10 feet tall.

Seldom found above 3,000 feet elevation, the rank-smelling arrowweed pluchea forms dense, willowlike thickets in streambeds 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 arrow shafts, 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.


Mimulus bigelovii (illustrated) Figwort family

Arizona and California deserts. Blooms red-purple. February-April.

Mimulus bigelovii (illustrated) Figwort family

Arizona and California deserts. Blooms red-purple. February-April.

Mimulus glabratus

Texas desert. Blooms yellow. June.

Size: Branching, creeping annual up to 8 inches.

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 monkey-flower 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 monkey-flowers 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 penste-mons.

The desert species are well worthy of consideration for cultivation as garden ornamentals.


Purplemat, Purple Roll-Leaf leaves in basal rosette and at ends of stems

stems prostrate

Nama demissum Waterleaf family

Arizona, California and Texas deserts. Blooms red-purple. March-May. Size: Tiny plant, an inch or so high.

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 flower 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.


Scarlet Spiderling, West Indian Boerhaavia x8 flower

x7 fruit

Scarlet Spiderling, West Indian Boerhaavia x7 fruit x8 flower

Was this article helpful?

0 0

Post a comment