ON FLOWERS AND INSECTS. 



[LECT. 



The Leguminosse, or Pea-tribe, present a number of 

 beautiful contrivances. Let us take a common little 

 Lotus corniculatus (Fig. 23). The petals are five in 

 number ; the upper one stands upright, and is known as 

 the standard (Fig. 24, std) ; the two lateral ones present 



a slight resemblance to wings 

 (Figs. 24, 25 w), while the two 

 lower ones are united along 

 their edges, so as to form a 

 sort of boat, whence they are 

 known as the "keel" (Figs. 

 25, 26 k}. The stamens, with 

 one exception, are united at 

 their bases, thus forming a tube 

 (Figs. 27, 28 t), surrounding 

 the pistil, which projects be- 

 yond them into a triangular 

 space at the end of the keel. 

 Into this space the pollen is 

 It must also be observed "that 

 each of the wings has a projection (c) which locks 

 into a corresponding 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 

 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. The 

 arrangement in the Sweet Pea is very similar, and 

 if the wings are seized by the fingers, and pressed 



FIG. 23. Lotus corniculatus. 



shed (Fig. 28, p). 



