LEGUMINOS^ 



151 



ledons is that frequently the cotyledons are subterranean 

 and do not leave the seed (Fig. 89). In some cases, 

 as, for instance, in the G-round Nut of the West Indies 

 [Arachis hypogcea), the plants themselves force the 

 seed-pods into the ground. Some foreign species, but 

 I believe no British, produce also cleistogamous flowers. 



Sarothamnus 



S. scoparius (Broom). — The stems are wiry and 

 green, having to some extent taken over the functions 

 of the leaves, which are small and sometimes almost 

 absent. The flowers produce no honey, but are visited 

 for the sake of the pollen. Of the ten stamens, five 



Pig. 92. 



Fig. 90. 



Fig. 91. 



Fig. 93. 



Figs. 90-93. — Sarothamnus (the Broom). 



Fig. 90. — Flower before explosion. 



Fig. 91. — Flower seen from above after removal of the standard and wings. 



Fig. 92. — Flower seen from the side after explosion of the short stamens. The 



standard and wings have been removed. 

 Fig. 93. — Flower seen from the side after complete explosion. 



are long and five short. When a bee alights on an 

 opening bud it presses its head under the standard, 

 and the pressure of its hind feet tends to separate the 

 wings and consequently to open the keel, which at. first 

 is closed by the cohesion of the upper edges (Fig. 92). 

 When this is opened to a certain distance the short 

 stamens suddenly appear (Fig. 93). The anthers had 

 already opened in the bud, and they thus dust the under 

 side of the bee with pollen. When the bud is older, or 

 if the bee exercises greater pressure, the split of the edges 



