Ch. VI, 5] METHODS OF CROSS-POLLINATION 



297 





(Kalmia), partly irritably, as in Barberry, and diversely in 

 some Orchids, though the exact significance of these and 

 other like phenomena is still matter of debate. 





Fig. 209. — Clusters of Larkspur, showing the diageotropism of the flowers. 

 The tip of the larger cluster was tied down at an early stage of its devel- 

 opment. (Drawn from a photograph.) 



There remains one leading question : Why these elaborate 

 arrangements for cross-pollination when close-pollination is 



i) 



