CHAPTKK XXVTT 

 CONTENTION WITH PHYSICAL ENVIRONMENT 



338. THE PHYSICAL ENVIRONMENT. We haw seen 



(326) that the environment in which a plant grows is 

 made up of two sets of factors the physical environ- 

 ment of climate and soil, and the organic environment 

 of competing animals and plants. 



339. ADAPTATION TO CLIMATE IN GENERAL. Ever J 



particular climate causes particular modifications in its 

 plants. There are two general ways, however, in which 

 plants are modified or adapted to climate: modification 

 in the length of tin period of growth; modification in 

 stature. Any modification of the plant, visible or invis- 

 ible, which adapts it to grow in a climate at firsl inju- 

 rious to it, is acclimatization. 



340. In short - season cliniates t plants hasten their 

 growth. They mature quickly. Indian corn raaj re 

 quire five or six months in which t<> mature in warm 

 countries, bul only three months in very <'<>ld countries. 

 Nearly all garden vegeta- 

 bles mature quicker from 

 the time of planting in the 

 North than in tin- South \ Jp 

 when the} aiv raisrd from .^^ . .rfM i. ii - 



Seeds grown in their Pes] Germination crown in 



, ... , , , New York (on thi una 



t ive I -.- 1 1 1 1 irs. Seedsmen fire 



aware of this and thej like to raise Beeds of earlj varieties 

 in the North, !'<>r such seeds asuallj give "early" plants. 

 Mans plant- which an' perennials in warm countries be- 

 come annuals or plur- annuals in cold countries (14). 



ill! At %#0k 



