192 NATURAL HISTORY OF PLANTS. 
obovate emarginate, and tapers below into a large claw with involute 
edges. The two lateral petals, called ale or “wings” (Fr., ales), 
symmetrical with respect to each other and far shorter and narrower 
than the standard, have an irregularly and obliquely oblong limb, 
with a lateral projection below and a long slender curved claw 
(fig. 141). The two anterior petals differ from both wings and 
standard in size and form, but resemble each other. The limb is 
irregular, and like the wing with the base of the inferior edge of its 
posterior border produced into an unsymmetrical auricle; it is un- 
equally wrinkled and bears on its outer surface, not far from the top 
of this auricle, a depression by which it clings to a corresponding 
projection on the inner face of the wing. The claw is here also 
slender and curved, and coheres for a certain distance along its 
inferior border with that, of the petal symmetrical. This close 
adhesion is prolonged all the way up the limb; so that the two 
anterior petals together form a single piece (fig. 142), which is 
termed the “keel” or carina (Fr., caréne). In the bud the keel is over- 
lapped by the wings, themselves again overlapped by the standard— 
an imbrication known as the vewillary prefloration. The androceum 
consists of ten stamens, subperigynous like the perianth ; five super- 
posed to the calyx-lobes, and five, shorter, to the petals. The 
filaments are diadelphous, the nine anterior being united below into 
a tube split along its superior edge, while the tenth, superposed to 
the standard, and hence termed the vexillary stamen, remains free 
on the superior side of the flower. The free summit of each filament 
bears an introrse two-celled anther of longitudinal dehiscence.’ The 
gyneceum, formed by a single carpel superposed to the anterior 
sepal, consists of a subsessile one-celled ovary surmounted by an 
inflexed style whose apex is dilated into a little stigmatiferous head, 
below which the dorsal edge of the style bears a thick tuft of hairs.? 
Above the wall of the ovary next the standard is a longitudinal 
placenta on whose two lips are inserted a variable number’ of de- 
1 The pollen is generally ovoidal or ellipsoidal 
in the group. Each group bears three longi- 
vernus, Lathyrus odoratus and pratensis, and 
Pisum sativum, 
tudinal folds, which in the spherical moistened 
grain are represented by either smooth or pa- 
pillose bands. H. Mout. (in Ann, Se. Nat., sér. 2, 
iii, 341) has found the latter condition in the 
pollen of Vicia Cracca and sylvatica, Orobus 
2 In the section Cracca (Rrv.,t. 52, nec L.) the 
style is slightly compressed from side toside, and 
the fruit bears an oblique dilatation at the apex. 
3 Unly two, or rarely three, as we have men- 
tioned in certain of the species of Erowm, which 
are now united with the genus Vicia, 
