

iv.] LOTUS. 



89 



their proboscis into the tube. In those species which 

 do not secrete honey this is unnecessary, and the 

 stamens are all fully developed and united. 



In the Common Birdsfoot Trefoil (Lotus cornicula- 

 tus] the anthers burst and emit their pollen before 

 the flower opens, and indeed before the petals have 

 attained their full size. At this time the ten stamens 

 form two groups, five of them being longer than the 

 others ; but by the time the flower opens they are 

 all of the same length, though the five outer ones are 

 somewhat swollen at the end ; a difference which sub- 

 sequently becomes still more marked. The pointed 

 end of the keel is now filled by a mass of pollen 

 (Fig. 70 and 71 po), while the anthers, having dis- 

 charged their contents, commence 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. 70 and 71. 



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. 70 e), which still have an important 

 function to perform, lie behind the pollen mass, and 

 keep it in its place. 



Insects do not generally alight directly on the keel, 

 but rather on the wings, which are more conveniently 

 situated ; the two, however, are relatively so arranged, 

 that when a bee alights on the wings, she presses 

 down the keel, which is locked with the two wings by 

 a projection and corresponding depression, as shown 



