226 



THE FLOWEK. 



Wistaria (Fig. 436-439), in which the light fringe of stiff hairs 

 around the stigma (shown in Fig. 439) would not prevent pollen 

 of surrounding anthers from falling upon it. Yet when a bee 



alights upon the keel, 

 with head toward the 

 base of the flower, and 

 proboscis is inserted 

 for nectar between the 

 foot of the standard 

 and the keel, the latter 

 is depressed by the 

 weight, so that the ab- 

 domen of the insect is 

 brought against the ten 

 anthers and the stig- 

 ma, becoming thereby 

 smeared with pollen, 

 some of which when 

 other blossoms are vis- 

 ited cannot fail to be applied to their stigmas. The very similar 

 flower of Locust (Robinia), like that of the Pea, adds an adapta- 

 tion in favor of intercrossing. The style for some length below the 

 stigma is covered with a short beard of hairs, as is 

 seen in Fig. 442. The Anthers open early and dis- 

 charge their pollen, which mainly lodges on this 

 beard (Fig. 443), in a manner which may thus far 

 be likened to the case of Campanula. (411.) The 

 wings and the keel are yoked together, and are 

 together depressed by the weight of an alighting 

 bee. This does not bring out the anthers as in 

 Wistaria, but these remain until effete within the sac, while the 

 stigma and the pollen-laden part of the style (Fig. 441) are 

 projected against the bee's abdomen, which, by the oblique 

 movement, is first touched by the stigma and next brushed over 

 with pollen by the style below. So that, in visiting a succession 

 of blossoms, some pollen of one flower is transferred to the body 

 of the bee, and thence to the stigma of the next flower, which 

 flower immediately gives to the same spot some of its pollen, to 

 be transferred to the next flower's stigma, and so on. 



417. Two special modifications of the papilionaceous type 



FIG. 440. Flower of Robinia hispida, the standard and wings removed. 441. Same, 

 as depressed by the weight of a bee, causing the stigma and pollen-laden tip of the style 

 to protrude. 442. Enlarged section of same in the bud, leaving one keel-petal, half the 

 stamens, and the pistil in view. 443. Style and stigma at a later period, the beard 

 loaded with pollen ; more magnified. 



