Different kinds of grasses have adapted themselves to different soils and altitudes and grow in company with different co-dominant plants. In colorful sequence the grasses create a three-dimensional mosaic that begins on the edges of the shrub desert, covering the foothills and running up through the woodlands out onto mountaintop meadows. You can see these differences quite easily. [Illustration: The U.S. Boundary Survey trekking the Big Bend country in 1852 encountered this Lipan Apache warrior. His portrait came to adorn the survey report.] Let’s say it’s ten o’clock on a fine fall morning, and you are driving from Rio Grande Village up to the Basin. You find shrub desert all around you at first, with the usual creosotebush, ocotillo, and pricklypear. The only grass you see grows in a buff-colored strip on either side of the road, where runoff from infrequent rains creates a habitat moist enough for grasses to germinate and reach maturity. But after you pass 900 meters (3,000 feet) of elevation you begin to see the first sparse bunches of chino grama spotted here and there across the desert. Somewhere just below the Dugout Wells turnoff you find quite a bit of bunch grass among the bushes. Almost imperceptibly the chino thickens until at 1,000 meters (3,500 feet) the hillsides appear cobbled over with lumps the color of gray rock. It appears that you couldn’t step down without stubbing your toe against a clump of gray-green grass or lechuguilla. Soon all the slopes are patterned yellow and gray-green as solid stands of lechuguilla crowd into the chino grama. The grass is so thick now that scaled quail hunt seeds along the roadside and cottontail rabbits bounce jauntily across in the mid-morning sunlight. The colors you see owe much to the angle of the sun, but at about 1,200 meters (4,000 feet), near Panther Junction, the plants themselves add a soft new hue, the beautiful silver-blue of ceniza shrubs. Bunches of vivid green grass crop up amid the tawny three-awns by the roadside, and the tops of the tarbush are brushed with yellow. Rock, gravel, grass, and shrub blend together in shades of tan, gray, green, and blue pinpointed by Christmas-red fruits on the guayacan, with once again vast gardens of chartreuse lechuguilla and skeleton-leaf goldeneye shrubs. These rolling grasslands have much less pricklypear and creosotebush, and they have a lower profile than the shrub desert. Here and there the Torrey yucca lifts its shaggy head high, but the whole land surface looks somehow smoother, less hob-nailed than before.