Yucca brevifolia
Common Names: JOSHUA-TREE, TREE YUCCA, GIANT JOSHUA California desert. (Yucca brevifolia). Green-white. February-April. Lily family. Size: 15 to 35 feet high; spread of 20 feet.
Because the presence of the grotesque Joshua-tree marks, more effectively than any other plant, the limits and extent of the Mohave Desert, this species is worthy of special recognition. This tree Yucca holds, in the Mohave Desert, similar status to the Saguaro in the Sonoran Desert. Strangely enough, in west-central Arizona, the Saguaro and Joshua-tree are found growing together and there the Sonoran and Mohave Deserts overlap.
And, just as in southern Arizona an area has been set aside as Saguaro National Monument to preserve and protect that species, so in southern California we find the Joshua Tree National Monument.
The Joshua-tree is outstanding among the many species of Yucca because of its short leaves growing in dense bunches or clusters, and because the plant has a definite trunk with numerous branches forming a crown. Great forests of these sturdy trees are found in parts of southern California, southern Nevada, southwestern Utah, and northwestern Arizona where rainfall averages 8 to 10 inches per year.
Flowers of this Yucca develop as tight clusters of greenish-white buds at the ends of the branches, but do not open wide as do the flowers of other Yuccas. Joshua-trees do not bloom every year, the interval apparently being determined by rainfall and temperature. Birds, a small lizard, wood rats, and several species of insects are closely associated with the Joshua-tree, making use of it for food, shelter, or nest-building materials. Indians use the smallest roots, which are red, for patterns in their baskets.
The name “Joshua-tree” was given by the Mormons because the tree seemed to be lifting its arms in supplication as did the Biblical Joshua.
WHITE
Yucca torreyi
Yucca schidigera
Yucca arizonica
Common Names: BROAD-LEAF YUCCAS, SPANISH BAYONET, (AMOLE), (DATIL), SOAPWEED Arizona desert. (Yucca arizonica). Creamy. April-May. California desert. (Yucca schidigera). White-purple. March-April. Texas desert. (Yucca torreyi). Creamy. March-April. Lily family. Size: Reaches height of 10 to 15 feet.
Although, in general, the Broad-leafed Yuccas do not reach tree size, the Giant Dagger (Yucca carnerosana) of Big Bend National Park reaches a height of 20 feet. In dense stands or “forests” these Yuccas, with their huge clusters of creamy, wax-like, lightly scented, bell-shaped flowers produce a never-to-be-forgotten display in blooming season.
The Yucca is the state flower of New Mexico.
Yuccas are often confused by newcomers to the desert with three other groups of plants: the Agaves (Century Plant), Dasylirion (Sotol) and Nolinas (Beargrass).
The plate on the opposite page has been devoted to a comparison of the four groups, and by studying it carefully, the characteristics by which each may be identified can be determined.
Yucca leaf fibers have long been used by Indians for fabricating rope, matting, sandals, basketry, and coarse cloth. Indians also ate the buds, flowers, and emerging flower stalks. The large, pulpy fruits were eaten raw or roasted, and the seeds ground into meal.
Roots of the Yuccas have saponifying properties and are still gathered by some tribes and used as soap, especially for washing the hair. Flowers are browsed by livestock. (See [Narrow-leaf Yuccas] and [Joshua-tree]). Yucca baccata, a broad-leaf species found in the Southwest outside of the desert areas, is discussed in “Flowers of the Southwest Mesas.”
CREAM
Common Names: BEARGRASS, BASKETGRASS, (SACAHUISTE) Arizona desert: (Nolina microcarpa). Tan-cream. May-June. California desert: (Nolina parryi). White-cream. May-June. Texas desert: (Nolina erumpens). White-cream. May-June. Lily family. Size: Ragged clumps 4 to 8 feet in diameter and flower stalks up to 8 feet high.
The Nolinas are sometimes confused with Sotol and the Yuccas and occasionally with the Agaves. However, the Nolinas resemble huge clumps of long-bladed grass, whereas Sotol leaves are ribbon-like and Yucca leaves taper to a sharp point. Flower stalks of the Nolinas are usually drooping and plume-like, and the numerous flowers are tiny. The many papery, dry-winged fruits often remain on the stalk until late autumn.
Beargrass does not grow on the flat mesas or sandy flats as do the Yuccas, but is confined to exposed locations on rocky slopes above the 3,000-foot elevation. The Parry Nolina of the California Desert is a larger and more spectacular plant than the species found in the Arizona and Texas-New Mexico Deserts. Indians are reported to use the very young flower stalks for food. Leaves are browsed by livestock in times of drought, sometimes with harmful results in the case of sheep or goats.
Nolina parryi
CREAM
Dasylirion wheeleri
Agave palmeri
Yucca elata
Nolina microcarpa
Common Names: SOTOL, SPOONPLANT Arizona desert: (Dasylirion wheeleri). Creamy. May-August. Texas desert: (Dasylirion leiophyllum). Creamy. May-August. Lily family. Size: Leaves 3 feet; flower stem 5 to 15 feet.
At first glance, this plant may readily be mistaken for a Yucca, but its ribbon-like leaves (which are usually split at the tips instead of sharp-pointed) and tiny flowers instead of the bell-like blossoms of the Yucca, are distinguishing characteristics. The round heads of these plants grow close to the ground with the thick, woody stem beneath the soil. Leaves, when stripped from the head, come away with a broad, curving blade.
When trimmed and polished, they are sold as curios called “desert spoons.” In some portions of the desert near large cities, exploitation of the plants for this purpose has endangered the species and aroused the ire of conservationists.
The cabbage-like base, after the leaves are removed, is split and fed to livestock as an emergency ration during periods of drought.
The rounded heads of these plants are high in sugar which is dissolved in the sap of the bud stalk. This sap, when gathered and fermented, produces a potent beverage called “sotol,” which is the “bootleg” of northern Mexico.
CREAM
Common Names: NARROW-LEAF YUCCA, (PALMILLA), OUR-LORD’S-CANDLE, SPANISH-DAGGER, SOAPWEED, SPANISH-BAYONET Arizona and Texas deserts: (Yucca elata). Creamy. May-July. California desert: (Yucca whipplei). Creamy-white. May-June. Lily family. Clumps 8-12 feet; Y. elata sometimes to 20 feet.
CREAM
The Narrow-leaf Yuccas are frequently confused with the Agaves (Century plant), Dasylirion (Sotol), and Nolinas (Beargrass) but may readily be recognized by the fibers protruding from the margins of the leaves. To permit comparison and bring out the differences so that the four groups may be recognized and confusion avoided, sketches of all four appear on the same plate ([p. 21]).
In many grassland areas of western Texas and southern New Mexico, Y. elata dominates the landscape for miles. This species has been used as emergency rations for range stock during periods of drought, the chopped stems being mixed with concentrates such as cottonseed meal. A substitute for jute has been made from the leaf fibers. Indians eat the young flower stalks, which grow rapidly and are relatively tender.
In its relationship with a moth of the genus Pronuba, the Yucca illustrates one of Nature’s interesting partnerships. The moth, which visits the Yucca flowers at night, lays her eggs in the ovary of a flower where the larvae will feed upon the developing seeds. But to be sure that the seeds do develop, the moth must place pollen on the stigma of the flower. Dependent upon the moth for this vital act of pollenization, the Yucca repays its winged benefactor by sacrificing some of its developing seeds as food for the moth’s larvæ. Fruits of the Narrow-leaf are dry capsules in contrast to the fleshy fruits of the Broad-leaf Yuccas.
Yucca whipplei is a much smaller plant than Y. elata, but produces a stouter flower stalk with a great spreading plume of small, delicate flowers. These graceful plumes appear at night as if aglow with an inner light, hence the name “Our Lord’s Candle.” (See Broad-leaf Yucca [[p. 19]] and Joshua-tree [[p. 18]].)
Clematis ligusticifolia
Clematis drummondi
Common Names: CLEMATIS, LEATHERFLOWER Arizona and Texas deserts: (Clematis drummondi). Cream. March-September. California desert: (Clematis ligusticifolia). Cream. May-September. Crowfoot family. Size: Climbing, vine-like perennial with stems 6 to 8 feet long.
By no means limited to the desert, Clematis is found throughout the Southwest. Several species are grown as ornamentals, foliage, flower clusters and the cotton-like masses of hairy fruits all being effective. Petals are absent or rudimentary, the sepals which furnish color to the blossoms being either creamy or purplish-brown. The name “Leatherflower” has been applied to the latter group.
CREAM