ee 
Rr eel 
i teieaniditieemenen ri. amet 
1901 | VEGETATION OF WESTERN TEXAS 263 
species are important elements: Cercocarpus parvifolius, Ribes 
uiscosissimum, Fendlera rupicola, Frasera speciosa, Geranium caespi- 
tosum, Campanula rotundifolia, Heuchera rubescens, Artemisia 
frigida, and Acer grandidentata. A few of these reach the sum- 
mits of the highest mountains in the Great bend, but scarcely in 
force enough to change the strongly upper Sonoran character. 
Hig. Y 
Cretaceous 
Edwards plateau. 
4.— Vegetation of adobe slopes and chalk exposures: characteristic of 
Texas, especially on the Grand prairie and the eastern half of the 
In the lower cafions, the dwarfed arborescent species of the 
xerophytic slopes become large trees of regular symmetrical 
growth. Thus, Quercus Emoryt ‘becomes a straight tree 2 to 4 
feet in diameter and 60 feet tall, forming the main feature of 
the sylva. Here also Pinus edulis attains the unusual size of 18 
inches in diameter and 40 feet in height” (Havard). These 
cafions contain in addition numbers of characteristically meso- 
phytic or semi-mesophytic woody species, as species of Prunus, 
Acer, Philadelphus, and Fendlera, while the sides of watered 
