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Plant Families


Some families are especially prominent in the Chihuahuan Desert or, if not of general prominence, have taxa within them of interest. The families listed below are only a small sample of the Chihuahuan Desert flora. We will be spending some time looking at these families. A larger number of Chihuahuan Desert plants is available on the Centennial Museum site. The links below will take you to some of these; for those of you interested in other examples, the Chihuahuan Desert plant list has a search engine. Entering the family name into the search engine will bring up links to representatives found in the Chihuahuan Desert.

Distribution within the USA as well as other information is available at the U.S. Department of Agriculture Plants Database website. Many other sites can be found with Google or other search engines, but the degree of trustworthiness can only be judged with experience.

Euphorbiaceae: Spurge Family. The spurges, or euphorbs as they often are called, belong to a widespread family concentrated in the tropics of the Old World and South America, but also into warm temperate regions, such as southern USA. There are some 245 genera and 6,000 species. Some familiar members include the Castor Bean, Manioc, and Poinsettia. Some of the plants sold in nurseries as cacti actually are euphorbs, some of which fill part of the cactus niche in Africa, particularly (the Cactaceae is a New World family). There is a wide variety of life forms, from small forbs to trees. Characteristically, the sap is milky and, in some subdivisions of the family, poisonous.

Among a number of euphorbs in the Chihuahuan Desert, Candelilla is well known to many of the public.

Rhamnaceae: Buckthorn Family. Another widespread family, especially in the tropics and subtropics. Most members are trees or shrubs, some are vines. Many bear thorns. In the Chihuahuan Desert, various shrubs belong to the family, including Graythorn, Texan Hogplum, Javelina Bush, and Warnock's Javelina Bush.

Fagaceae: Beech Family. Although commonly known as the beech family, the oak family would be a better common name. The Chihuahuan Desert has a large number of oak species, although above the true desert for the most part. One of the elevationally lower is Scrub Oak. Another is Arizona White Oak. The large number of oak species produce acorns important as wildlife food.

Anacardiaceae: Sumac Family. Also known as the cashew family, the cashew being one of the well known members. Others include the Mango and Pistachio and, of course, everyone's favorite: Poison Ivy. Several widespread shrubs of this family occur in the Chihuahuan Desert, including Rhus microphylla and Rhus trilobata. The former is widespread in desert habitats; the latter more common in foothills and canyons and at higher elevations. Several other shrubs of the genus Rhus occur in the region as does, usually at higher elevations, Poison Ivy.

Rosaceae: Rose Family. The rose family is well represented in the Chihuahuan Desert Region with several prominent members, including Apache Plume, Southwestern Chokecherry, California Rosewood, and Mountain Mahogany.

Cactaceae: Cactus Family. Cacti often are thought of as epitomizing the desert. Although the Chihuahuan Desert lacks the tree-like giant cacti of the Sonoran Desert, the diversity of the family in the Chihuahuan Desert is astounding. Generally characterized by a body consisting of stems with no leaves and spines galore, body form, flower color, and spinous arrangements are diverse. Only a few can be considered here. The prickly pear cacti, consisting of a number of species, have their stems flattened into pads; flowers occur along the edges of the pads. These, and many other cacti, have edible fruits known as tunas. Other members of the same genus (Opuntia) have elongated, cyclindrical stems and are known generally as cholla or cane cacti. The barrel cacti normally consist of a single, corrugated body. Smaller and without the corrugations are such cacti as the hedgehog cacti. Pincushion cacti are aptly named. A number of other cacti are pictured on the Plant List pages.

Fabaceae: Pea Family. This was long known as the Leguminosae (and that name is still used by some). It's the second largest family of plants, with some 18,000 species. Some authorities divide it into three families, characterized primarily by flower type. All have in common the type of fruit known as a legume; this is a pod-structure that splits along two sides, with seed attached along one or both seams. Numerous plants important economically belong to this family, providing food (e.g., beans, peanuts), ornamental plants (e.g., Acacias), fodder (clover, alfalfa), and commercial chemicals (dyes, tannins). Legumes generally are associated with bacteria that live in nodules on the roots; these bacteria fix atmospheric nitrogen into forms usable by plants, and often legumes such as alfalfa are planted as organic fertilizer; this is particularly important in desert regions, where the low level of usable nitrogen often is a limiting factor. Kudzu is an introduced vine that wreaks havoc in the southeastern USA. Many of the members of the family have pinnate leaves, each leaf divided into leaflets or more complicated divisions.

Only a small sampling of Chihuahuan Desert legumes is given here. Certainly Honey Mesquite is a major component of the desert. Its nutritious beans are utilized by many desert animals and, in the past, by Native Americans. Historically, desert grasslands of the Chihuahuan Desert were overloaded with grazing stock. With a combination of overgrazing and drought, much of the grasslands were degraded into Chihuahuan Desertscrub. Cattle spread undigested mesquite beans far and wide, so that it's believed that mesquite is much more common now than in earlier times. In areas with a sandy substratum, we often end up with mesquite hummocks.

A different species of mesquite, Screwbean Mesquite (Tornillo), prefers floodplain habitat. Various species of acacia occur throughout the desert. Retama (Parkinsonia aculeata) is an introduced species from south of the desert, but is widely spread as an ornamental and as an escapee quite at home along arroyos. Mescal Bean (Mountain Laurel) is common in limestone areas to our east in east-central New Mexico through southern Texas and northern Mexico.

Onagraceae: Evening Primrose Family. Numerous species of evening primroses are widespread throughout our region. These plants bloom in the evening through the night, but soon wilting in the light of day. Flowers usually are white, yellow, or pinkish. The flower of the Baja Evening Primrose is typical.

Chenopodiaceae: Goosefoot Family. Four-wing Saltbush is a prominent member of this family, found throughout the region. Another prominent member is the introduced Tumbleweed.

Sapindaceae: Soapberry Family. Western Soapberry is a member of this family, as is Mexican Buckeye. Among familiar plants sometimes placed in the family are the maples (Acer).

Zygophyllaceae: Caltrop Family. Although several other species of the family occur in the Chihuahuan Desert, it's considered here because it includes one of the dominant shrubs of the Chihuahuan Desert: Creosotebush, Larrea tridentata. This shrub is typical of the North American hot deserts, often dominating large segments of the desert basins. It's presumed to have reached its dominant position in what once were desert grasslands when overgrazing and drought knocked down grass species to where they were unable to successfully compete with the Creosotebush. Thanks to its noxious chemical makeup, it is largely immune to herbivorous attack.

Tamaricaceae: Tamarix Family. As with the Zygophyllaceae, this family is considered here solely because of one member, Salt Cedar. Introduced from the Old World originally as an ornamental and for erosion control, this plant has invaded virtually all of the waterways of much of the West, the Southwest, and northern Mexico. There are several species possible. Tamarisk is highly tolerant of both salty and alkaline condition. It tends to crowd out native species from the floodplain while supporting little in the way of wildlife. Control has thus far been ineffective. As a phreatophyte (a plant with its roots into the ground water), it transpires enormous amounts of water from rive-maintained ground water, resulting in reduced flow for wildlife, irrigation, and urban use.

Solanaceae: Potato Family. A number of species occur in the desert region. A common weed is Silverleaf Nightshade. Tobacco is a prominent member of the family and includes wild species in the desert. More apt to be a problem to humans is the usage of Sacred Datura by youths for its hallucinogenic features. Every year tends to bring at least a few deaths due to miscalculation.

Fouquieriaceae: Ocotillo Family. Ocotillo is prominent in the hot deserts of North America. It tends to favor foothills or other areas of rough topography. It's noted for its ability to drop it leaves during periods of drought and very quickly grow a new crop when wetter conditions return. The bright orangey-red flowers often appear when the stems are otherwise bare.

Cucurbitaceae: Gourd Family. Several kinds of gourds are common in the desert. These are widely utilized by wildlife and, in the past, by American Indians.

Lamiaceae: Mint Family. This family has been known as the Labiatae, also. A large number of species occur in the Chihuahuan Desert Region. Members of the genus Salvia are widely planted as ornamentals. The common name of "sage" is applied to several groups of plants not at all closely related. "Sage" often is applied to various members of this family, such as Mexican Blue Sage.

Salicaceae: Willow Family. The willows and cottonwoods are included in this family. Both are closely tied to sources of water and the original bosques that crowded the floodplains of the Rio Grande had both as prominent members. The Coyote Willow is an example.

Scrophulariaceae: Figwort Family. Several genera are important ornamentals as well as constituents of the desert flora. Members of the genus Leucophyllum are widely planted as drought-resistant shrubs that bloom profusely several times during the hot season. These often are called rain sages because blooming often quickly follows a rain. Another genus highly prized for the beauty of its members is the genus Penstemon.

Acanthaceae: Acanthus Family. Several shrubs with rather spectacular flowers belong to this family. Dwarf Desert Honeysuckle is a good example, though other species have somewhat brighter colors.

Bignoniaceae: Catalpa Family. The Desert Willow is a prominent, small tree along desert drainageways in the Chihuahuan Desert. It also is widely planted as an ornamental and in highway beautification programs. Yellow Bells is common in the desert ranges of the northern desert and widely planted as an ornamental.


Asteraceae: Sunflower Family. The Asteraceae (commonly called the Compositae in the past and often called composites as an overall common name), along with the Fagaceae and Cactaceae, tends to dominate the Chihuahuan Desert. Characteristically, what we tend to think of as the flower of members of this family actually consists of a number of flowers (florets) gathered together to form the head. In a representative species, there are a number of non-showy flowers making up a disk (and thus often called disk flowers or florets) that is surrounded by one or more layers of showy ray flowers. In the accompanying photograph, the 22 ray flowers each have a large, yellow petal; the disk consists of several hundred small, brownish flowers. A number of permutations on the basic setup occur; some have no ray flowers, some have no disk flowers, and there is much diversity in terms of numbers of florets, etc.

The examples given here are only a very small portion of desert composites. One composite that often is considered as a Chihuahuan Desert marker is Tarbush. Members of the genus Parthenium are widespread; Parthenium confertum has been used as a source of latex and was attempted to be raised for rubber during the second world war. Artemisia filifolia (Sand Sagebrush) is a prominent shrub in areas with a sandy substratum. The Desert Marigold is one of a plethora of yellow composites seen in the desert as is the fall-blooming Turpentine Bush. Many composites, such as Firewheel, Gayfeather, and Mexican Hat (Cone Flower) are raised as ornamentals.

Poaceae: Grass Family. Grasses are widespread, though less so than in earlier historic time. Black Grama is the common grama grass of the desert grasslands, though other species such as Hairy Grama also occur.

Agavaceae: Agave Family. Many of the desert lily-like forms have been shuffled from family to family. As used here, the agaves, yuccas, sotols, and bear grasses are included in the Agavaceae. A large number of species occur in the Chihuahuan Desert, of which we are giving only a sample. The agave Lechuguilla often is considered as a marker for the Chihuahuan Desert. The alternative name of Shindagger is apt, for this small agave is well situated to drive the spine-tipped leaves into the lower leg. In common with other agaves, it has not only a sharp point to the leaf, but a series of strongly hooked, sharp teeth along the margin of the leaf. Agaves commonly are called century plants under the common impression that they bloom only after 100 years of growth. Although the growth period is long, it doesn't approach the 100-year mark. When sufficient food has been stored, a flowering stalk is quickly produced, the plant blooms, and after ripening of the fruit, the plant dies.


Last Update: 25 Jun 2006