68 THE STORY OF THE PLANTS. 



prolongation at the end of the leaf (Fig. 12). It 

 IS provided with a lid, and its rim secretes a sticky 

 sweet liquid. Insects that enter the jug are pre- 

 vented from escaping by strong recurved hooks; 

 and these hooks are so powerful that at times they 

 have been known even to capture small birds which 

 had incautiously entered. This may seem curious, 

 but it is not odder than the fact that our own Eng- 

 lish bladderivort, a water plant with pretty yellow 

 flowers, which grows in sluggish streams, has sub- 

 merged bladders that supply it with manure, not 

 only from water-beetles, larvae, and other insects, 

 but also from trout and other young fry of fresh- 

 water fishes. I may add that while the sundew 

 and other live-insect catchers have to digest their 

 prey, the water-trap makers save themselves that 

 additional trouble and expense by macerating and 

 soaking it till it reaches the condition of a liquid 

 manure, ready dissolved for absorption, and easy 

 to assimilate. 



Thus we see that while roots are the chief or- 

 gans for absorbing nitrogenous matter, they are 

 often supplemented in special circumstances by 

 leaves and stems. Moreover, in many cases leaves 

 also supply the plant with water. On the other 

 hand^ roots often fulfil yet another function, by 

 storing up food for the plant from one season to 

 another. It is true this is still more often done 

 by underground stems, but the distinction between 

 the two is very technical, and I do not think I 

 need trouble you here with it. Large trees with 

 solid trunks usually lay by their starch and other 

 valuable materials over winter in a peculiar living 

 layer of the bark ; and here it is on the whole 

 fairly free from danger. Still, even in trees the 



