REPRODUCTIVE ORGANS 
115 
FIG. 115. A winged seed of Bignonia. After STRASBUBGER. 
spores called pollen 
and occasionally 
falling upon the 
right spot for 
germination. 
With such an 
agent of transfer 
the pollen must 
be very light and 
powdery, and 
also very abun- 
dant, for it must 
come down al- 
most like rain to be 
grains being scattered by the wind, 
FIG. 117. 
Winged fruit of 
KEKNEB. 
FIG. 116. Winged fruit of maple. After KERNER. 
certain of reaching the right places. 
Among the gymiio- 
sperms (pines, hem- 
locks, etc.) this is the 
exclusive method of 
pollination, and when a 
pine forest is shedding 
pollen the air is full of 
the spores, which may 
be carried to a great 
distance before being 
deposited. Occasional 
Ptelea. After 
