HOW PLANTS DRINK. 76 



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 lower part of the bark is often 

 nibbled by such animals as rabbits ; and to 

 prevent this mischance most smaller plants bury 

 their rich food- stuffs underground during the cold 

 season. For whatever will feed a young plant 

 or a growing shoot will also just equally feed an 

 animal. Hence the frequency with which plants 

 make hoards of their collected food-stuffs under- 

 ground, for use next season. The potato is a 

 well-known instance of such underground hoards ; 

 the plant lays by in what are technically sub- 

 terranean branches a supply of food- stuff for 

 next season's growth. These branches are 

 covered with undeveloped buds, which the 

 farmer calls '* eyes " ; and from each of these 

 eyes (if the potato is left undisturbed, as nature 

 meant it to be) a branch or stem will start 

 afresh next season. It will use up the starch 

 and other foodstuffs in the potato, till it reaches 

 the light ; and there it will begin to develop 

 green chlorophyll, and to make fresh starch for 

 itself, and young leaves and branches. 



An immense number of plants thus lay by 

 underground stores of food for next season's 

 use. Such are the carrot, the beet, and the 



