1885.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 477 



and proportions of the South Carolina tree. The Long Moss ( Tillandsia 

 usneoides), found as far west as San Antonio, becomes a marked feature 

 of the vegetation near the coast. 



At and about Brownsville the most common trees are, as above, 

 Retama, Huisache, Hackberry, Willow, and Mezquit, the latter extend 

 ing down the river nearly to its mouth. 



HILLS, BLUFFS, AND MESAS. 



The most widespread and common tree on hills and bluffs, from the 

 Canadian River to the Rio Grande, is the Red Cedar (Juniperus oc- 

 cidentalis aud var. conjungens), generally of small size and gnarled 

 growth. Next in frequency is the low round-headed Gray Cak (Quercus 

 grisea), particularly conspicuous on the grassy bluffs southwest of Marfa. 

 The Post Oak (Q. stellata) is found on ridges near the Gulf Coast and, 

 in thin groves, on high ground farther inland, north of the Nueces 

 River. It is a good-sized tree in the Buffalo Gap Mountains, south of 

 Abilene, its extreme western limit in Texas. The Red Oak (Q. rubra) 

 often extends from valleys to the base of hills and mountains but is 

 nowhere large or abundant. The shrubby Q. undulata begins at the 

 Pecos River and occurs occasionally in clefts of rocky bluffs along the 

 Rio Grande. 



On some of the high ridges and peaks of the mountainous region north 

 of the Chisos Basin, from the Santiago Range to Peiia Colorado, and 

 thence nearly to Fort Davis, are seen small scattered Nut Pine (Finus 

 edulis), and, at a lower altitude, clumps of shrubby Ash (Fraxinus cus- 

 pidata and Greggii) and Mulberry (Mortis microphylla). Nut Pine is 

 also sparingly found on the bluffs of the forks of Nueces River and 

 further north along the edge of the escarpment of the Staked Plains. 



Very prominent on foot-hills and bluffs are : the Bear- Grass or Sotol 

 (Dasylirion Texanum), the pestilent Lechuguilla (Agave heteracantha), 

 the handsome Jacob's Staff or Ocotillo (Fouquiera splendens) whose 

 thorny shoots are tipped with racemes of scarlet flowers, the forbid- 

 ding Spanish Bayonet or Palmo ( Yucca baccata) in all stages of growth, 

 the smaller Yucca angustifolia, the tufty Nolina, Texana and erumpens. 



On low slopes and banks of ravines abounds the Texas Persimmon 

 (Diospyros Texana), and common are several species of Sumach (Rhus 

 microphylla, trilobata and virens). 



On the craggy, limestone hill-sides of the west, we find habitually the 

 Sangre de Dragon (Mozinna spathulata), the leafless Euphorbia antisyph- 

 ilitica, the bushy Mortonia scabrella, the long-tubed Macrosiphonia Ber- 

 landieri, the curious moss-like Siempre Vive (Selaginella lepidophylla) 

 and its congener S. rupestris, several Ferns (Notliolama and Fellcea). 



In the Great Bend of the Rio Grande, the bluffs are often covered with 

 decayed argillaceous schist, giving them a repulsive blackish and* cin- 

 dery appearance. Even then they are seldom entirely bare but mostly 



