Farther west two narrow belts of timber, consisting mostly of stunted post oak and black jack, and known as the Eastern and Western Cross Timbers, cross the prairies southward from the Red river, and a low growth of mesquite, other shrubs and vines are common in the eastern half of the Prairie Plains.
Bouteloua with numerous species (mesquite grass, grama grass) on the plains of the south-western United States, afford good grazing.
The Lower Sonoran zone is noted for its cactuses, of which there is a great variety, and some of them grow to the height of trees; the mesquite is also very large, and the creosote bush, acacias, yuccas and agaves are common.
From the lake is Death Valley (including Lost or Mesquite Valley) - the name a reminder of the fate of a party of " forty-niners " who perished here, by thirst or by starvation and exposure.
In the arid portions of this and the tropic areas the indigenous plants are creosote, mesquite and alfileria bushes, desert acacias, paloverdes, alkali-heath, salt grass, agaves, yuccas (especially the Spanish-bayonet and Joshua tree) and cactuses.
The Mesquite Gulf is to the N.W., the Gulf of Darien to the N.E., and on the N.
Another variety, obtained from the Prosopis dulcis, a leguminous plant, is called gum mesquite or mezquite; it comes from western Texas and Mexico, and is yellowish in colour, very brittle and quite soluble in water.
There is but little natural vegetation to be seen - ragged yucca trees, many species of agave and cactus, scrubby mesquite bushes, sage bushes and occasional clumps of coarse grasses.
In the Lower Sonoran belt, soapweed, acacias (Palo Verde or Parkinsonia torreyana), agaves, yuccas and dasylirions, the creosote bush and mesquite tree, candle wood, and about seventy-five species of cactuses - among them omnipresent opuntiae and great columnar " Chayas " - make up a striking vegetation, which in its colours of dull grey and olive harmonizes well with the rigidity and forbidding barrenness of the plains.
The mesquite varies in size from a tangled thorny shrub to a spreading tree as much as 3 ft.