388 H. Engelmann on vegetation known as 
which have been excessively wet in the spring suffer considera- 
bly from drought, in a great measure certainly because the sub- 
soil is naturally too close, and not opened by deep rooting plants, 
and therefore does not assist in the absorption of the moisture 
from the air, nor attract much of it from the water below. 
Grasses which are not only able to withstand, but even delight 
ie: & 
Prof. J. D, Whitney, the distinguished State geologist of Cali- 
in his report on the physical geography of lowa, 
art 1, of the Geological report of Iowa: “Taking 
