With the arrival of the Spanish and Anglo-Americas, more than 500 species of grasses covered Texas. Although plowing and lack of soil conservation destroyed a considerable portion of this rich heritage, grassy pastureland still covers about two-thirds of the state. Bermuda grass is a favorite ground cover, especially an improved type called Coastal Bermuda, introduced after World War II. Texas has more than 20 native trees, of which the catclaw, flowering mimosa, huisache, black persimmon, huajillo, and weeping juniper (unique to the Big Bend) are common only in Texas. Cottonwood grows along streams in almost every part of the state, while cypress inhabits the swamps. The flowering dogwood in East Texas draws tourists to that region every spring, and the largest bois d'arc trees in the US are grown in the Red River Valley. Probably the most popular shade tree is the American (white) elm, which, like the gum tree, has considerable commercial importance.
In 2003, 28 Texas plant species were listed as threatened or endangered, including ashy dogweed, black lace cactus, large-fruited sand-verbena, South Texas ambrosia, Terlingua creek cats-eye, Texas snowbells, Texas trailing phlox, and Texas wild-rice.
Red wolf is the rarest mammal found in Texas. It inhabits the marshland between Houston and Beaumont, one of the most thickly settled areas of the state. However, due to human interference, and possible hybridization with coyotes, the red wolf is steadily disappearing despite efforts by naturalists throughout the United States to save it. On the other hand, Texans claim to have the largest number of white-tailed deer of any state in the Union, an estimated 3 million. Although the Hill Country is the white-tailed deer's natural habitat, the species has been transplanted successfully throughout the state. The nine-banded armadillo is perhaps the most unsual mammal found in Texas.
Texas attracts more than 825 different kinds of birds, and 100 species of snake. In 2003, 63 animal species were listed as threatened or endangered in Texas (up from 43 in 1997), including the Mexican long-nosed bat, bald eagle, Houston toad, ocelot, Mexican spotted owl, Texas blind salamander, Louisiana black bear, black-capped vireo, two species of whale, and five species of turtle.