ADAPTATIONS FOR INTERCROSSING. 



225 



and, as the plants or stems are single-flowered, the}' are function- 

 all)' dioecious while structurally hermaphrodite. 



413. The adaptations for hermaphrodite intercrossing with 

 synanthesis (407) , i. e. where there is no essential difference of 

 time in the maturing of anthers and stigma, are manifold. 

 The}' may be classed into those without and those with dimor- 

 phism of stamens and pistils, or, in other words, those with 

 Homogenous and those with Heterogonous flowers. 1 



414. The cases without dimorphism are the most various, 

 certain families having special types ; and are of all degrees, 

 from those that require intercrossing to those that merely favor 

 or permit it. For the present purpose, having only morphology 

 in view, it suffices to bring to view two or three cases or types of 



415. Particular Adaptations in hermaphrodite blossoms, not 

 involving either dichogamy or dimorphism. These are exceed- 

 ingly various ; but they may be distinguished into two general 

 kinds, namely: 1, where loose and 



powdery pollen is transported from 

 blossom to blossom in separate grains, 

 and 2, where pollen-masses or the 

 whole contents of anthers are bodily 

 so transported. 



416. Papilionaceous flowers (such 

 as pea-blossoms, 338) having ten 

 stamens enclosed with a single pis- 

 til in the keel 



of the corolla, 

 their anthers in 

 close proximity 



4T8 



to the stigma 



were naturally 



supposed to be 



self-fertilizing ; and so they sometimes are, jet with marked 



adaptations for intercrossing. None are less so than those of 



1 Terms proposed in Amer. Jour. Sci. ser. 3, xiii. 82, and in Amer. 

 Naturalist, January, 1877. Dimorphism in flowers may affect the perianth 

 only, and not the yovf) or essential organs ; or there may be two kinds of 

 flowers as respects these also, but with no reciprocal relations, as in cleisto- 

 yamous dimorphism (534) ; or of two kinds essentially alike except in stamens 

 and pistil, and these reciprocally adapted to each other, which is heterogonous 

 dimorphism, or, when of three kinds, trimorphism. 



FIG. 436. Flower of Wistaria Sinensis natural size. 437. Same enlarged, with 

 standard, wings, and half the keel removed. 438. Same with the keel depressed, as it 

 is when a bee alights on this its usual landing place, the cluster of anthers and stigma 

 thus brought up against the bee's abdomen. 439. Style and stigma, with part of the 

 ovary, more magnified, a fringe of fine bristles around the stigma. 



15 



