18 

 reason for the reduced surface. It is almost luilversal that the 

 shade form of a plant is larger than the sun form, as poison ivy. 

 Kerner's theory does not account for this. As iron go up the plant 

 the need is for protection, as you go down, for liglit. 



- Wliy is the grass form so successful ? The verticality allows 

 a greater number of leaves, hori?:;ontal position is test for the 

 individual. Verticality and reduction represent the best type 

 of adaptation to light. 



