LIGHT AND HEAT 69 
The Fixed Light-Position of Leaves.—Every leaf takes 
up a fixed position with regard to the light, and this 
position is that in which it receives the maximum average 
/\~ Fie. 20.—Cimeine SHoor or Ivy, sHowrne 
/ ; Lear-Mosato. 
Fic. 21.—FiLowerrine SHoor or Ivy with LEAVES STANDING OUT ON 
ALL Smpes or STEM. 
amount of light. This, of course, is only true of those 
herbaceous forms of leaves which spread out horizontally 
to catch as much light as possible. In xerophytes the 
