Euphorbia antisyphyilitica

Euphorbia antisyphyilitica is (Candelilla) a member of the Euphorbiaceae. This is a large and diverse family, and some Euphorbiaceae-- particularly those from hot and dry regions of Africa--resemble members of the Cactaceae. However, these similarities do not reflect common ancestry, as the Cactaceae and Euphorbiaceae clearly are not closely related. The name of this species of Euphorbia comes from the use of the juice to treat syphilis. The plants have a waxy covering which can be isolated by boiling the plants and scooping the wax off the surface. This is a high quality wax and its desirability has resulted in the eradication of this plant from many areas.

Koeberlinia spinosa

Koeberlinia spinosa (Allthorn) more than merits its common name. There is only one species in this genus and it is a member of the Capparidaceae (Capparaceae). Quail use the plant for cover and eat the fruits.

Sarcostemma on Lycium texanum

Sarcostemma (in flower with long narrow leaves that are wider at the base) is a member of the Asclepiadaceae (Milkweed Family). This vine is growing on the shrubbyLycium texanum (Texas Wolfberry), which is a member of the Solanaceae.

Ziziphus obtusifolia

Ziziphus obtusifolia (Gumdrop Tree) is a member of the Rhamnaceae (Buckthorn Family). The fruits it produces are drupes which are eaten by birds and small mammals.

Atriplex obovata

Atriplex obovata (Saltbush) is a member of the Chenopodiaceae (Goosefoot Family).

Populus deltoides

Populus deltoides (Cottonwood) is a member of the Salicaceae (Willow Family). The seeds have long hairs attached to them which aid in wind dispersal. You would see large amounts of what looks like cotton flying around when the seeds are released.


The genus Quercus (Oaks) is a member of the Fagaceae (Beech Family). These are trees with alternate leaves that produce a fruit called an acorn. Acorns are nuts partially covered by a cup composed of bracts (the cap). Acorns are generally not edible by humans due to their very bitter taste. They are usually identified by looking at leaf and acorn characters, but this can be difficult due to variability in their morphology. It is not unusual to encounter plants that are intermediate between two species and it is thought that at least some of this variability is caused by hybridization.

Quercus gambelii (Gambel Oak)

Quercus turbinella (Scrub Oak)

Quercus undulata

Mortonia sempervirens

Mortonia sempervirens (Rough Mortonia) is a member of the Celastraceae (Stafftree Family). This plant has erect whitish stems.

Celtis pallida

Celtis pallida (Spiny Hackberry) is a member of Ulmaceae (Elm Family) and, as the name implies, is spiny. Unlike most members of Celtis , it is a shrub rather than a tree.

Prunus harvardii

Prunus harvardii (Harvard Plum) is a member of the Rosaceae (Rose Family). The fruit type of Prunus is an edible fruit called a drupe. Some cultivated members of Prunus include cherry, peach, and plum. Surprisingly, almonds also produce drupes but the fleshy part that is edible in all the others is not edible in almonds. Thus, almonds are really not nuts but endocarps (stones) with edible seeds inside.

Rhus trilobata

Rhus trilobata (Fragrant Sumac) is a member of the Anacardiaceae (Sumac Family). Poison ivy and poison sumac are also members of this family, but Fragrant Sumac is not poisonous. As the common name indicates, it is rather aromatic. The main function of aromatic compounds in plants is probably to hinder their consumption by animals.



The genus Acacia is in the Mimosaceae (Mimosa Family) or the subfamily Mimosoideae of the Fabaceae (Leguminosae or Legume Family), depending on the particular reference that you are using. They can be trees or shrubs, many have spines or prickles, and the white to yellow flowers occur in tight clusters. Some are important browse plants for wildlife and some are valued for their nectar, an important component of honey production in some areas.

Acacia roemeriana

Acacia schottii

Parthenium argentatum

Parthenium argentatum (Guayule) is a member of the Asteraceae (Compositae or Sunflower Family). This particular species is known for its production of high quality rubber

Caesalpinia gilliesii

Caesalpinia gilliesii (Bird-of-Paradise) is in the Caesalpiniaceae or subfamily Caesalpinioideae of the Fabaceae. The flowers are very attractive and the plant is used as ornamental. Notice the long red filaments (a part of the stamens). The leaves and seeds may be poisonous.