ORDERS 83 
enclosing the gynecium. The posterior stamen—that is, the 
one opposite the standard—is free. | | 
In order to see that the corolla and andreecium are perigynous, 
the flower should be cut vertically in the median line (Fig. 106). 
It will then be evident that the petals and staminal tube are 
attached to the edge of a shallow cup-shaped receptacle. 
Gynecium : one carpel, superior. 
Frat: a pod or legume. 
This may be eed in the Broom (Cytisus 
scoparius). Fig, 108 shows the flower unopened, 
with the keel in a state of tension almost parallel to the 
standard. An insect alighting on the wings of the corolla, 
and thrusting its head below the standard, presses down the 
Pollination. 

Fics. 103 ro 110.—PoLLINATION oF Broom (Cytisus scoparius). 
108.—KEEL IN STATE OF TENSION. 109.—KEEL DEPRESSED AND Four 
STAMENS PROTRUDING. 110,—SipeE Virw or ANDRGCIUM AND 
GYNAECIUM AT SAME STAGE. 
keel (Fig. 109), the upper edge of which splits; the four outer 
stamens spring out, and the under side of the bee’s body gets 
dusted with pollen. Meanwhile the keel goes on splitting, and 
as soon as the split reaches the part where the point of the style 
lies, it springs up, striking the back of the bee, which is covered 
with pollen from another flower ; thus the stigma is pollinated. 
The other five stamens then explode more violently than 
the first, depositing more pollen on the bee’s back ; this will be 
carried to another flower. Cross-pollination does therefore take 
place, and Darwin noted that if insects did not visit this flower, it 
seldom made seed. (“Fertilisation of Flowers,” Muller, p. 195.) 
Other The plants belonging to this Order are very 
Plants. varied in their growth; some are creeping—e.4., 
Clover ; others are climbing, some by means of their tendrils— 
