ECOLOGY OF LEAVES 111 
Fic. 78. Leaves standing nearly Vertical in Compass-Plant 
(Silphium laciniatum). 
A, view from east or west; B, from north or south. 
129. Movements of Leaves and Stems toward or away 
from Light (Heliotropic Movements). — The student doubt- 
less learned from his experiments with seedling plants 
that their stems tend to seek light. The whole plant 
