82 GROWTH AND WORK OF PLANTS 



teeth of a steel trap. Upon the upper face of each side of the leaf 

 are three prominent hairs. When these hairs are touched the 

 second time, the leaf suddenly closes like a trap. Flies which 

 alight on the leaf are thus caught and pressed between the folded 

 leaf, and the leaf excretes, through special glands, juices which 

 digest portions of the insect, which are then absorbed by the leaf 

 and used for food. The sundew has a rounded or elliptical leaf 

 blade covered with long glandular hairs which excrete a sticky 

 substance. When an insect alights on the leaf the sticky substance 

 holds it, and the hairs and leaf slowly fold inward around the insect 

 and it is digested by the glandular juices. 



