LEGUMINOS.i: 



153 



(Figs. 99, 100, po), while the anthers, having discharged 

 their contents, begin to shrivel up. The free ends of the 

 five outer stamens continue, however, to increase in size ; 

 so that, with the pollen mass, they completely fill up the 

 cavity of the keel. When the flower opens, the pistil, 

 stamens, and pollen occupy 

 the position shown in Figs. 

 99, 100. The five inner 

 stamens, having discharged 

 their pollen, have become 

 useless, shrivelled up, and lie 

 in the broader part of the 

 keel ; the five outer ones, on 

 the contrary (Fig. 99, /), 

 which still have an im- 

 portant function to perform, 

 lie behind the pollen mass, 

 and keep it in its place. 



Each of the wings has a 

 projection (Fig. 97, c) which 

 locks into a corresponding 

 depression of the keel (Fig. 98, c), so that if the wings 

 are depressed they carry the keel with them. Now, 

 when an insect alights on the flower, its weight 

 depresses 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. It 

 will be observed (Fig. 99) that one stamen is separated 

 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 Leguminosse 

 which have no honey the stamens are all united 

 together. Such flowers are, nevertheless, in spite of 

 the absence of honey, visited by insects for the sake 

 of the pollen. 



Fig. 95. — Lotus c(rrniculatus. 



