172 
PAPILIONACEOUS FLOWERS. 
there is a symmetry and equality in their parts. There may 
be slight inequalities in regular corollas ; as in the lily we 
sometimes see some petals a little longer than the others ; this 
is an exception to the general rule. Irregular corollas are vari- 
ous in their forms ; the papilionaceous seem as they stand upon 
their stem to consist of an upper and under part ; the calyx is 
monosepalous, ending in five distinct leafy points, the two 
upper ones wider than the three under ones. The peduncle is 
slender and flexible (see Fig. 148, g) ; thus the flower readily 
avoids a current of air by turning its back to the wind and rain. 
Suppose we have before us a pea-blossom ; we see the corolla 
is polypetalous. The large petal covering the others and occu- 
pying the upper part of the corolla, is the standard or hanner. 
This petal is evidently designed to protect the stamens and 
other parts of the flower from injuries by the weather. Upon 
talcing off the banner we find that it was inserted by a little 
process or projecting part into the side pieces so that it could 
not easily be separated by winds. The wings are strongly in- 
serted into the remaining part of the corolla. Upon removing 
the wings we discover a part of the corolla, called on account 
of its form the keel [carina)^ or boat. Upon drawing the 
keel downward, we find ten stamens (double in number to 
the petals) are joined together by the sides of their filaments, 
forming a cylinder which surrounds the pistil. One of the 
stamens, however, does not adhere to the rest ; but as the 
flower fades and the fruit increases, it separates and leaves an 
opening at the upper side, through which the ovary can extend 
itself by gradually opening the cylinder. In the early stage of 
the flower, this stamen seems not to be separated ; but by 
carefully moving it with a pin or needle, its filament will be 
found unconnected with the other nine stamens. 
251. The ovary of the papilionaceous plant extends itself into 
that kind of pod called a legume. It is distinguished from the 
silique of the cruciform family by having no partition in the 
legume. Besides the seeds grow to one side only ; but in the 
silique pod they are alternately attached to both edges of the 
partition. The legume opens lengthwise and rolls backward ; 
in the silique, the valves separate and diverge from the base 
upward. The seeds of this family have a scar, or line, called 
the Mlum^ by which they adhere to the pod. l^ear the hilum 
there is a minute opening into the body of the seed, through 
which moisture is imbibed at the period of its first growth or 
germination. The ovule continues to swell, and at length 
bursts through the coats of the seed, presenting between the 
550. Regular and irregular corollas — Analjsis of the pea-blossom. — 251. Distinctioa between Uw 
legume and silique — Seeds oi' the leguminous tribe. 
