186 BOTANICAL GAZETTE [SEPTEMBER 
vegetation there, not only in the summer, when an abundance of 
water is usually available for the vegetation, but in those critical 
periods of winter and early spring, when, owing to the low 
temperature of the soil, water is not readily absorbed. 
Another important influence of wind upon vegetation consists 
in its effects upon cross-pollination and dissemination. Obviously 
the conditions are particularly favorable for wind-pollination on 
the marshes (and by that very fact somewhat unfavorable for 
insect-pollination), and the same is true for wind dissemination. 
We shall see later how much the vegetation is influenced by 
these factors. 
[ Zo be continued. | 
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