204 



PHYSICAL ENVIKONMENT 



341. Even germination is usually more rapid from 

 northern-grown seeds than from southern - grown seeds 

 of the same kind. The plants "come up" quicker. Se- 

 cure seeds of the same variety of corn or bean grown 

 in the Gulf states and in the northern states or Canada 

 and make the experiment (Fig. 350). The same results 



often show in 



the vegetation 

 of cuttings of 

 trees and grape 

 vines from the 

 South and 

 North . Vege- 

 tation is quick 

 in the North : 

 the "burst of 

 spring" is usu- 

 ally more rapid. 

 342. Plants 

 are usually 

 dwarf or smal- 

 ler in stature in 

 short-season cli- 

 mates. Indian 

 corn is a con- 

 spicuous example. As one ascends high mountains or 

 travels in high latitudes, he finds the trees becoming smal- 

 ler and smaller, until finally he passes beyond the regions 

 in which the trees can grow. Many of the Esquimaux 

 doubt the statements of travelers that there are plants as 

 high as a man. In these high altitudes and high latitudes, 

 plants tend also to become prostrate. 



343. PLANTS ARE INFLUENCED BY WIND. In regions of 

 strong prevailing winds, as on lake and sea shores and on 

 hills and mountains, tree-tops develop unsym metrically 







351. Evergreen trees on -wind-swept heights of the 

 Rocky Mountains. 



