ECOLOGY OF WOODLAND PLANTS. 373 
Figs. 18, 20, 22, 24, 26, & 28, 
(o2 
5 
Ul- 
ec 
Q 
S 
d 
è 
rA 
i 
is 
Ty 
D 
K 
0 
us 
{ ) 
= 
20 
Leaf-stalks of Pteris aquilina, showing variations in the development of 
stercom in plants growing under different conditions, 
