1885.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 463 



The San Pedro, or Devil's Eiver, is a large stream draining a hilly, 

 grassy district, interesting alike to botanist, sportsman, and stockman. 

 More or less timber is fonud all along its course, consisting of Pecan, 

 Sycamore, Mulberry, Hackberry, Soapberry, and Willow, with shrub- 

 bery of Persimmon, Granjeno, Mezquit, and Frijolillo. In the vicinity 

 of old Fort Hudson are groves of Live Oak. Between the bridge of the 

 Southern Pacific Eailroad and the old crossing,- a distance of 3 miles, I 

 observed four species of Grapes : Vitis cestivalis, riparia, rupestris and 

 candicans, with intermediate forms, all growing luxuriantly. 



Below Eagle Pass, the Rio Grande receives no tributary on the Texas 

 side. Many arroyos drain the vast plains stretching from the Nueces 

 and the Olmos Elvers to the boundary line, and several retain more or 

 less rainwater, but there is no permanent running stream emptying into 

 the Rio Grande from Eagle Pass to Brownsville. 



Many streams, some becoming important rivers, take their origin along 

 the eastern edge of the Staked Plains. I shall review them briefly as 

 they appear within our limits. 



THE CONCHO. 



The Concho and its tributaries run through undulating, grassy plains. 

 From Fort Concho we can trace their course for several miles by Pecan 

 trees of luxuriant growth ; they are also fringed in places with Live Oak, 

 American Elm ( Ulmus Americana)^ more sparsely with Cottonwood and 

 everywhere with Hackberry. On the Main Concho the timber, thick 

 below, becomes scant a few miles above Fort Concho, but scattered 

 clumps extend as far as Camp Charlotte. On the North Concho there 

 is good timber, restricted to the banks, as far as Sterling Creek. A small 

 wild Plum {Prunus rivularis) with red, palatable fruit, is common on the 

 Concho and Colorado. Dense thickets of Mezquit cover many of the 

 surrounding high table-lauds. 



The most common Grasses in the Concho Basin and northward are, 

 Buchloe <?acfy?o?*<7es (BuflVilo-Grass), Aristida purpurea, Bouteloua oligos- 

 tachya (Common Grama), and Hilaria mutica, all, but specially the first 

 and third, of excellent quality. The first two are commonly called 

 Mezquit-Grass. 



Decking the prairie on all sides, are the cherry-red Gallirrhoe pedata, 

 the Prairie Lily {Cooperia Drummondii)^ and the ubiquitous Verbena 

 bipinnatijida, Monarda citriodora, Salvia far inacea. 



THE COLORADO. 



At Austin, the capital of Texas, the picturesque banks of the Colo- 

 rado are well timbered with Pecan, Cottonwood, Sycamore, Cypress, 

 several species of Elm and of Oak. The latter are : Quercus virens (Live 

 Oak), Q. rubra (Red Oak), Q. nigra (Black Jack), Q. macroearpa (Bur 

 Oak), Q. stellata (Post Oak), Q. palustris. The White-heart Hickory 



