228 FLASHLIGHTS ON NATURE 



for growth next season. About the time when the 

 pond grows cool, the buds detach themselves, like 

 the winter shoots of the pond-weed, and slowly 

 descend by their own weight to the bottom. But 

 they do not root themselves there, as the pond-weed 

 shoots did ; they merely lie by, like the whirligig 

 beetles, as you can see one of them preparing to 

 do in the left-hand corner of No. 10. All the 

 living material is drained from the leaves into 

 these winter bulbs. The pond freezes over, and 

 the remnant of the floating leaves decay ; but the 

 bulbs lurk quietly in the warm mud of the bottom, 

 protected by a covering of close-fitting scale- 

 leaves. 



In No. 1 1 we learn the end of this quaint little 

 domestic drama. Spring has come, and the pond 

 has thawed again. The winter buds of the frogbit 

 now undergo certain spongy internal changes, due 

 to warmth and growth, which make them lighter 

 lessen their specific gravity. Air-cells are deve- 

 loped in them. So they begin to rise again like 

 bubbles to the surface. You can see in the illus- 

 tration one bud still entangled in the slime on the 

 bottom ; another just starting to emerge ; a third 

 rising ; and a fourth and fifth on the surface of 

 the pool. Two more have already risen ; one of 

 these is just putting forth its first few kidney-shaped 

 leaves ; another has now grown pretty strong, and 

 is sending out a runner, from which a third little 

 plant is even beginning to develop. In time, hun- 

 dreds of such runners are sent forth in every 

 direction, till the surface of the pond, in suitable 



