206 BOTANICAL GAZETTE [SEPTEMBER 
Edwards plateau, cut off by the cafion of the Pecos river. On 
the west the province adjoins the eastern front ranges of the 
mountains. Most of this area is a typical grass plain formation, 
of the general type found on the Staked plains and on the 
plains portion of the Edwards plateau. It will be seen that 
t so 
G. 10.—Chaparral formation at Corpus Christi; the growth shown is ae 
tall as dias which covers the country generally in this region; the genera are C 
Opuntia, Condalia, Zizyphus, and Celtis, 
nearer the Rio Grande the surface is more broken, and that here 
woody vegetation predominates, also that the chaparral forma- 
tion is encroaching even upon the level grass plains. 
Compared with the Edwards plateau, this province as a whole 
is more elevated, and is in a zone of less rainfall and of greater 
evaporation capacity. It is more intimately a part of the arid 
sei a iam 
