ANTHOPHTTA. 



281 



rounding the flower-heads of some thistles. Whether the 

 small insects thus caught are made use of by the plants in 

 any way is as yet uncertain. 



533. In the Sundews (Fig. 168), which are common 

 little bog-plants, the leaves have many stalked glands which 



FlQ. 168.— A Sundew-plant (Droaera). Natural size. 



secrete a sticky substance. These glands are sensitive, and 

 when an insect comes in contact with one or more of them 

 and is held fast the others slowly bend towards the insect, 

 and the leaf itself rolls up, completely surrounding the 



