434 
LEGUMINOSAE 
The corolla is polypetalous, alternating with the calyx; its aestiva- 
tion may be valvate (Mimosoideae), ascending imbricate (Caesalpinioi 
deae), or descending (Papilionatae). In many cases it is zygomorphic 
to a high degree, having a large petal posterior (vexillum or standard), 
Floral diagrams of Vicia Faba (Papilionatae) and Acacia latifolia 
(Mimosoideae), after Eichler (modified). 
two lateral (alae or wings), and two anterior more or less joined 
to form a keel or carina. The androeceum consists typically of 
io sta., free or united into a tube ; in the latter case the tenth 
sta. (the posterior one) often remains free, so as to leave a slit 
in the tube, only covered loosely by this sta. Many variations from 
the typical androeceum are found. In cases where a keel is present, 
the sta. are enclosed in it. 
The gynoeceum consists typically of one cpl. with its ventral side 
directly posterior; it has a long style and terminal stigma. There 
are two rows of ovules (they alternate with one another so as to stand 
in one vertical rank), anatropous or amphitropous, ascending or 
pendulous. 
Fertilisation. Only the Papilionatae have as yet been at all 
thoroughly studied (and only the European genera of these). The 
keel encloses the essential organs, protecting them from rain, &c. and 
rendering the fir. so complex that only the cleverer insects can make 
much of it. Honey is secreted by the inner sides of the sta. near 
their base, and accumulates in the stamen-tube round the base of the 
ovary. In order to render the honey accessible, the tenth sta. is 
free of the tube, and at the base, on either side of it, are two open- 
ings leading to the honey. The honey is thus concealed and at some 
depth, so that a clever insect with a tongue of moderate length is 
required. All this points to the P. being bee-flowers, as in fact is the 
case. Insects visiting the firs, alight upon the wings and depress 
them by their weight, whilst they probe for honey under the standard. 
The wings are always joined to the keel, usually by a protuberance in 
the former fitting into a suitable hollow in the latter, so that the keel 
is thus depressed likewise. This causes the emergence of the essential 
organs, the stigma usually coming first, so that a fair chance of cross- 
