28 FURZE BROOM. [CHAP. 



(Fig. 28, p). It must also be observed that each of 

 the wings has a projection (c) which locks into a cor- 

 responding depression of the keel, so that if the wings 

 are depressed they carry the keel with them. Now 

 when an insect alights on the flower, its weight de- 

 presses the wings, and as they again carry with them 

 the keel, the latter slips over the column of stamens 

 thus forcing some of the pollen out at the end of the 

 keel and against the breast of the insect. As soon 

 as the insect leaves the flower, this resumes its natural 

 position, and the pollen is again snugly protected. 

 The arrangement in the Sweet Pea is very similar, 

 and if the wings are seized by the fingers, and pressed 

 down, this out-pumping of the pollen may be easily 

 effected, and the mechanism will then be more clearly 

 understood. 



It will be observed (Fig. 28) that one stamen is sepa- 

 rated from the rest. The advantage of this is that it 

 leaves a space through which the proboscis of the bee 

 can reach the honey, which is situated inside the tube 

 formed by the united stamens. In those Leguminosae 

 which have no honey, the stamens are all united to- 

 gether. Such flowers are, nevertheless, in spite of the 

 absence of honey, visited by insects for the sake of the 

 pollen. 



In other Leguminosae, as, for instance, in the Furze 

 (Ulex europ(Eiis\ and the Broom (SarotJiamnus scopa- 

 rius), the flower is in a state of tension, but the differ- 

 ent parts are, as it were, locked together. The action 

 of the bee, however, puts an end to this ; the flower 

 explodes, and thus dusts the bee with pollen. 



Whole volumes might be filled with the various 



