276 SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
The ash weighed 265 pounds per acre, or between 4 and 5 per cent 
of the air-dry weight. 
According to some of the old inhabitants, the Plains vegetation 
formerly grew taller than it does now. This probably does not 
mean that the Andropogon scoparius was any taller, but that the 
taller grasses, such as А. furcatus and Sorghastrum (which are 
said to be more characteristic of the fertile prairies of the West), 
were more abundant. If that is true the annual growth per unit 
area must be decreasing, which is consistent with the suggestion 
on a preceding page about the progressive impoverishment of 
the soil. And the fact that the groves of pines at Island of Trees 
are composed of rather small trees appears to indicate a com- 
paratively recent invasion, which would be in harmony with the 
same tendency, for Pinus rigida, like most other pines, flourishes 
in very poor soils. But one would hardly suppose that the soil 
could deteriorate so rapidly that the difference in vegetation would 
be noticeable in a lifetime, and there may be some entirely different 
explanation for the supposed change in vegetation. 
The vegetation characteristic of the wet valleys is very limited 
in extent. The largest stream on the Plains is East Meadow 
Brook, which rises about three miles east of Garden City and flows 
south about a mile before passing into the forest region. Most 
of its vegetation within the prairie area has been destroyed in the 
last few years, unfortunately, and the brook itself is nearly dry 
now, but pretty full notes were taken therein 1907-1909. Hemp- 
stead Brook, which flows through the eastern part of the village 
of Hempstead, is next in importance, and there is a smaller brook 
about two miles farther west which still has a trace of its original 
vegetation. : 
Along the streams there are no trees except a few small 
specimens of Acer rubrum and Nyssa, scarcely rising above the 
shrubbery, but the shrubs are considerably larger than those of 
the uplands, many of them being higher than a man's head. Fire 
seems to be a negligible factor in the environment 
The meadow plants are divided into small trees and shrubs, 
vines and undershrubs, herbs and mosses. Otherwise the treat- 
ment is the same as that of the upland vegetation, the rarer 
species being omitted, for the reasons already given. 
