100 



ELEMENTS OE BOTANY. 



nearly upright, with their edges approximately north and 

 south, Pig. 86, so that the rays of the midsummer sun will 

 during every bright day first strike the leaf-surfaces at right 



Fig. 86. — Leaves standing nearly Vertical in Compjiss-Plant 

 {Silphium laciniatvm). 



angles, then be nearly parallel to them, and again ' toward 

 sunset strike them at right angles. 



126. Movements of Leaves and Stems toward Light. — The 

 student doubtless learned from his experiments with seedling 



