54 



to protrude. The stamens and pistil come in contact with 

 ■ the lower surface of the body. When the insect leaves the 

 flower the parts return to their positions. At the base of the 

 expanded part of the wings is a pouched swelling 

 which causes the wings to cohere with the keel and serves the 

 purpose ot bringing these back to their positions. Honey 

 bees are the active pollinators. It is also pollinated by small 

 Lepidoptera. Short tongued insects are included. Self-fer- 

 tilization seldom if ever takes place. Darwin found that 

 wlien insects are excluded it is but slightly productive. 



Sweet Peas. The flowers of sweet peas are conspicuous 

 as to odor and color. The margins of the wings 

 of the corolla adhere to the keel by a process which folds 

 inwardly, the standard also fits into these wings. It thus 

 requires considerable force to press down the keel which 

 contains the pistil and stamens. The style is flattened and 

 hairy along the inner side. These hairs contain the pollen 

 and as the keel is pressed down the pollen is swept out. 



Amorpha fruticosa, L. The flowers are purplish and 

 arranged in a conspicious spike In this plant the keel and 

 wings are wanting and the standard surrounds the stamens 

 and pistil which are exserted. The flowers are proterogyn- 

 oiis, here at Ames as elsewhere, as observed by Trelease, 

 Robertson, Mueller and Beal. It is visited by Bombus and 

 the honey bee here at Ames. 



The Lead Plant, A. canescsns, Nutt., flowers nearly a 

 month later at Ames and is not a competitor with it as it 

 grows in diflerent situations. 



Partridge Pea. This leguminous plant is conspicu- 

 ous in dry situations and has some interesting 

 features, first described by J. E. Todd. These are described 

 by Robertson as follows: "The sickle shaped pistil is turned 



