REPRODUCTIVE ORGANS 



115 



Fig. 115. A winged seed of Bignonia.— After Strasburger. 



spores called pollen 

 and occasionally 

 falling ujDon 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 

 Kerner. 



Fig. 116. Winged fruit of maple.— After Kerner. 



certain of reaching the right places. 

 Among the gymno- 

 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.—Xfler 



