262 DKOSEBA ROTUNDIFOLIA. CHAP. XL 



CHAPTEK XL 



RECAPITULATION OF THE CHIEF OBSERVATIONS ON 

 DROSERA ROTUNDIFOLIA. 



As summaries have been given to most of the 

 chapters, it will be sufficient here to recapitulate, as 

 briefly as I can, the chief points. In the first chapter 

 a preliminary sketch was given of the structure of the 

 leaves, and of the manner in which they capture 

 insects. This is effected by drops of extremely viscid 

 fluid surrounding the glands and by the inward 

 movement of the tentacles. As the plants gain most 

 of their nutriment by this means, their roots are very 

 poorly developed ; and they often grow in places 

 where hardly any other plant except mosses can 

 exist. The glands have the power of absorption, 

 besides that of secretion. They are extremely sen- 

 sitive to various stimulants, namely repeated touches, 

 the pressure of minute particles, the absorption of 

 animal matter and of various fluids, heat, and gal- 

 vanic action. A tentacle with a bit of raw meat on 

 the gland has been seen to begin bending in 10 s., 

 to be strongly incurved in 5 in., and to reach the 

 centre of the leaf in Lalf an hour. The blade of the 

 leaf often becomes so much inflected that it forms a 

 cup, enclosing any object placed on it. 



A gland, when excited, not only sends some in- 

 fluence down its own tentacle, causing it to bend, but 

 likewise to the surrounding tentacles, which become 

 incurved ; so that the bending place can be acted on 

 by uu impulse received from opposite directions, 



