Ch. VI, 



METHODS OF CROSS-POLLINATION 



297 



(Kalmia), partly irritably, as in Barberrj^, and diversely in 

 some Orchids, though the exact significance of these and 

 other hke 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 froiu a photograph.) 



There remains one leading question : Why these elaborate 

 arrangements for cross-pollination when close-polliuation is 



