4 RELA TION OF PLANTS AND INSECTS. [CHAP. 



In by far the majority of cases, the relation between 

 flowers and insects is one of mutual advantage. In 

 some plants, however, as for instance in our common 

 Drosera, we find a very different state of things, and 

 the plant catches and devours the insects. 1 The first 

 observation on insect-eating flowers was made about 

 the year 1768, by our countryman Ellis. He observed 

 that in Dionaea, a North American plant, the leaves 



FIG. 4. Drosera rotnndifolia. 



have a joint in the middle, and thus close over, kill, 

 and actually digest any insect which may alight 01 

 them. 



In our common Sundew (Drosera rotundifolia, 

 Fig. 4) the rounded leaves are covered with glutinous 

 glandular hairs or tentacles on an average about 200 

 on a full-sized leaf. The glands are each surrounded 



1 See Danvin's Insectivorous Plants. 



