ADAPTATIONS FOB INTERCROSSING. 



225 



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

 ally 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. 

 They ma}* be classed into those without and those with dimor- 

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

 Homogonous and those with Heterogonous flowers. 1 



414. The cases without dimorphism are the most various, 

 certain families having special t}'pes ; 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 



to the stigma 



were naturally 



supposed to be 



self-fertilizing; and so they sometimes are, yet 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 yov-fi or essential organs ; or there may be two kinds of 

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

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

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

 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 



