244 ' AGRICULTURE. 



II. Variation Furnishes the Starting-point. 



1. Variation of Seedlings. 



2. Variation may be induced by 



(1) ENVIRONMENTAL CHANGES. 



(a) Change in Food-supply. 



(b) Light Relations. 



(c) Pruning. 



(2) CROSS-FERTILIZATION. 



(a) Limits of Crossing. 

 (b} Varying Results of Crossing 

 (c} Process of Cross-pollination 

 3 Bud Variation, 



HI. Fixing the Type. 



C REFERENCES, 



