The Chihuahuan Desert is the largest North American desert.

Typical plants & succulents of the Chihuahuan Desert include:

agave, prickly pear, chollas (the most common in the Big Bend area is the Cane Cholla), ocotillo, creosote bush, tarpaper bush, lechuguilla (Spanish for "little lettuce"), whitethorn acacia, peyote cactus, yucca, sotol, candelilla, and crucifixion thorn.

Over 70 species of cacti occur in Big Bend National Park. Among them: Southwestern Barrel Cactus, Devil's Claw (or "Horse Crippler"), and Strawberry Cactus.

250 species of cacti occur throughout the Chihuahuan Desesrt. Lacking are the various columnar cacti associated with the more-westerly Sonoran Desert (of mostly Arizona & Mexico).

Typical trees of the Guadalupe Mountains include:

Ponderosa Pine, Douglas Fir, Quaking Aspen, Chokeberry, and Pinon.
In the sheltered canyons of those mountains:
Big-tooth Maple, Walnut, Chinquapin Oak, Alligator Juniper, and the beautiful & rare Texas Madrone.

The Chisos Mountains woodlands are dominated by:

pinon, oak, and juniper.
The Drooping Juniper occurs outside of Mexico only in the Chisos. Also there, and  not normally outside of Mexico, are: Chinquapin Oak and the Coahuila Scrub Oak.