Flowers. 



corpus- 



the top stands exactly beneath the slit in 

 culum. 



The surface of the flower 

 is slippery, so that when a 

 bee, for instance, visits it, 

 a good foothold is not ob- 

 tained until the bee slips 

 Its foot into the recess be- 

 tween the anthers, termed 

 the stigmatic chamber (m). 

 Having obtained a foot- 

 hold, the bee thrusts its 

 sucking apparatus into the 

 hollow nectar receptacle 

 and obtains the nectar 

 which has invited it to the 

 flower. When the bee, 

 however, seeks to go to 

 another flower, its foot 

 slips upward and becomes 

 caught in the slit in the 

 corpusculum. A struggle 



now ensues which usually 



FIG. 108. 



Diagram of a flower of Asclepias cornuti. , surface view of a flower, showing 

 the opening into the stigmatic chamber at m, the upward-pointing nectar recep- 

 tacles, and the reflexed petals. F, longitudinal diagram of a flower ; s, sepal ; 

 p, petal ; n, one of the pistils ; r, stamen and nectar receptacle growing from it ; 

 o, pollen sac ; v, nectar receptacle, with stigmatic chamber between it and the 

 cavity containing the pistils. G, cross diagram of a part of a flower ; m, stig- 

 matic chamber; o, pollen sac; n, apices of the pistils. H, diagram showing 

 the relation of the pollinia to the stigmatic chamber; w, pollinium ; x, connect- 

 ing rod or retinaculum. y, corpusculum or clip. The pollinia are in the 

 pollen sacs and the clip stands over the stigmatic chamber. /, semi-diagram- 

 matic view of a flower, showing the pollinia in position (as if the pollen sacs 

 were transparent) ; outline of pollen sacs shown with dotted lines ; at the top 

 of the pollen sacs are slits through which the pollinia are to be pulled out. 

 J, showing the pollinia partly removed from the pollen sacs. WISE. 



