198 THE STORY OF THE PLANTS. 



There is, in short, no essential difference between 

 the two processes of growth and reproduction. 



Again, in the common lesser celandine the root- 

 stock emits a large number of tiny pill-like tubers, 

 which grow and lay by rich material underground 

 (derived from the leaves) during the summer sea- 

 son. In the succeeding spring, however, each of 

 these tubers develops again into a separate plant, 

 in a way with which the familiar instance of the 

 potato has made us familiar. In the crocus, 

 once more, and many other bulbous plants, sev- 

 eral small bulbs are produced each year by the 

 side of the large one, and these smaller bulbs are 

 of course, strictly speaking, mere branches of the 

 original crocus-stem. But they grow separate at 

 last, by the decay or death of the central bulb, 

 and themselves in turn produce at their side yet 

 other bulbs, which become the centres of still 

 newer families. We may parallel these cases with 

 those of trees whose boughs bend down and root 

 in the ground so as to become in time independ- 

 ent individuals; or with runners like those of the 

 strawberry and the creeping buttercup, which root 

 and grow afresh into separate plantlets. 



Sometimes still more curious things happen to 

 plants in the way of reproduction by subdivision. 

 There is an English pondweed, for example, which 

 grows in shallow pools liable to be frozen over in 

 severe winters. As cold weather approaches, the 

 top of the growing shoots in this particular pond- 

 weed break off of themselves, much as leaves do 

 at falling time. But they break off with all their 

 living material still preserved w r ithin them undis- 

 turbed; and they then sink and retire to the 

 unfrozen depths of the pond, where they remain 

 unhurt till spring comes round again. This is 



