FLOWERS AND INSECTS 



251 



flower the stamens are short and included in the tube, 

 while the style is long and projecting, with the four stig- 

 matic lobes exposed well above the corolla (Fig. 246, A). 



FIG. 246. Flowers of Houstonia: A, form with short stamens and long style; 

 form with long stamens and short style. After GRAY. 



In the other flower the relative lengths are exactly reversed, 

 the style being short and included in the tube, and the 

 stamens long and projecting (Fig. 246, B). It appears 

 that the pollen from the short stamens is more effective 

 upon the short style; and that the pollen from the long 

 stamens is more effective upon the long style. The body 

 of the visiting insect fills the corolla tube and projects 

 above it. In visiting flowers of jDoth kinds, one region of 

 the body receives pollen from' the short stamens, and 

 another region from the long stamens. In this way tfce* 

 insect is soon carrying about two bands of pollen, which 

 come in contact with corresponding stigmas. 



