194 



Introduction to Botany. 



results in the bee pulling the two pollen masses, united 

 to the corpusculum, through the narrow slits (as in / 

 and J) at the tops of the pollen sacs ; and thus laden, it 

 seeks another flower, and there slips its foot, together 

 with the pollen masses, into the stigmatic chamber. 



Now when the bee attempts 

 to leave the flower, the pollen 

 masses become tightly wedged 

 at the narrow apex of the cham- 

 ber, and a hard pull is required 

 to break them loose from the 

 foot. Finally, as the foot is 

 being drawn from the stigmatic 

 chamber it catches into the cor- 

 pusculum directly above and 

 pulls out a second pair of pollen 

 masses. Thus the bee goes from 

 flower to flower and from plant 

 to plant, repeatedly pulling pol- 



Photograph of a honey bee gathering . 



nectar from an Asdepias flower, len masses from their sacs and 

 One leg is still fast in a stigmatic depositing them in the stigmatic 



chamber of the flower last visited. 



chambers. Figure 109 is a pho- 

 tograph of a honey bee gathering nectar from Asdepias 

 flowers. One of the hind legs is still held in the stigmatic 

 chamber of the flower which the bee has just deserted. 

 Referring to Diagram G, note that the pollinia are re- 

 moved by the bee from the pollen sacs o, o, and de- 

 posited in another flower in the stigmatic chamber m. 

 The bee always inserts its foot in m both in removing 

 the pollinia and in depositing them. 



While the honey bee is the most important cross pollina- 

 tor of this plant, butterflies and wasps are also of service. 



After the pollinia have been deposited in the stigmatic 



FIG. 109. 



