218 THE STORY OF THE PLANTS. 



vitality in this way. They will grow again from 

 the merest cut end under favourable conditions. 

 These few short hints as to the life-history of 

 various plants in different circumstances will 

 serve to show you how vast is their variety. 

 Every plant, indeed, has endless ways and 

 tricks of its own ; and every point in its 

 structure, however unobtrusive, has some 

 purpose to serve in its domestic economy. Thus 

 the ivy-leaved toad-flax, which grows on dry 

 walls, has straight flower-stalks, which become 

 bent or curved when the flowering is over. 

 Why is this ? Well, the plant has acquired the 

 habit of bending round its flower-stalk after the 

 blossoming season, because it cannot sow its 

 seeds on the bare stone, so it hunts about 

 diligently for a crevice among the mortar into 

 which it proceeds to insert its capsule, so that 

 the seedlings may start fair in a fit and proper 

 place for their due germination. So, too, the 

 subterranean clover, growing on close-cropped 

 hillocks much nibbled over by sheep, where its 

 pods of rich seeds would be certainly devoured 

 if exposed on a long stalk like that of other 

 clovers, has developed a few abortive corkscrew- 

 like blossoms in the centre of its flower-head, 

 by whose aid the whole group of pods burrows 

 its wayj spirally into the soil beneath ; so that 

 the plant thus at once escapes its herbivorous 

 enemies, and sows its own seed for itself auto- 

 matically. It would be impossible in our space 

 to do more than thus briefly indicate by two or 

 three examples the immense number and variety 

 of these special adaptations. Every plant has 



