Igo! | VEGETATION OF WESTERN TEXAS IOI 
5 
aon para ON 
a ee 
1G. I1.— Physiographic provinces and minor subdivisions of the greater Texas 
region.— From Hill’s Phys. Geog. Texas. 
that the northernmost part is 10.5° removed from this, is at 
an elevation of 5000 feet, and directly exposed to the extremes 
of continental climate; and that in the latitude of 32° a moun- 
tain mass reaches the height of goo0o feet; we have an indica- 
tion of the range of annual temperature for the region under 
discussion. The temperature conditions of the lower Rio Grande 
valley from October to April are about the same as those of the 
middle third of the Florida peninsula. Those of the Staked 
plains above 4000 feet are about the same as those of the south- 
ern half of Kansas, Missouri, and Illinois. Again, the daily 
