early days, he had seen Smith's Agropyron as thick and tall as wheat covering thousands of acres of basin soil, and that it was common practice in those days to cut it for hay to tide over the winter. The more pervious and water-conservative 14 of the soils of the uplands also supported good growths of the same grass—a perennial, stoloniferous, coarse, sod-forming species.
Below the caprock the steep slopes connecting with the lands below, whether with the canyon floor or with the surrounding eroded plain, are covered with scant timber, of which cedar is the most common dominant, growing in open stand upon grassland. Along permanent water courses cottonwoods are common on the wide, open canyon floors; while scrubby hackberry, elm, willow, wild china and plum increase in size and height in proportion as the narrowing canyon gives greater protection from the sweep of drying winds, and as soil water becomes more abundant. In places embody ing unusually favorable conditions, sizable trees are not uncommon.
Grasses are in the main the same as are found on the level up land; but the aspect is changed by the addition of other species, such as Stipa meo-mexicana, S. spartea, Muhlenbergias, triple-awn and other grasses. Colorful wild flowers are Astragalus and many other legumes, buckwheat allies, spiderworts, wild onions, docks, evening primroses of great variety and profusion, four o"1 clocks, mustards, borages, scrophs and a wealth of composites of every shade, hue and size.
Clinging to the ledge of caprock and about the precipitous sides of steepest canyon walls are shrubs of Condalia, Ephedra, Yucca, Nolina, Havard's oak, plum, Acacias, Mimosa, and mesquite. Grape, Smilax, Clematis, moonseed and perhaps Cissus and Ampelopsis are not uncommon vines in moist shaded situations.
The region as a whole is very fertile and rainfall is high enough in wet years to produce good crops of wheat, grain sorghums, and cotton; while the use of machinery in cultivation and harvesting greatly increases the acreage an individual can tend. The result is that the region has been transformed within the past quarter century from a cattle country to an agricultural region. Dry-land
The Vegetation of Texas