DROSERA. 175 



itats, and experimented with each. They all behave in 

 a similar manner — capturing insects, and digesting and 

 absorbing the soft parts. Mr. Darwin (" Insectivorous 

 Plants," p. 17) says: "The absorption of animal mat- 

 ter from captured insects explains how Drosera can 

 nourish in extremely poor peaty soil — in some cases 

 where nothing but sphagnum moss grows, and mosses 

 depend altogether on the atmosphere for their nourish- 

 ment. Although the leaves at a hasty glance do not 

 appear green, owing to the purple color of the tentacles, 

 yet the upper and lower surfaces of the blade, the pedi- 

 cels of the central tentacles, and the petioles contain 

 chlorophyl ; so that, no doubt, the plant obtains and 

 assimilates carbonic acid from the air. Nevertheless, 

 considering the nature of the soil where it grows, the 

 supply of nitrogen would be extremely limited, or quite 

 deficient, unless the plant had the power of obtaining 

 this important element from captured insects. We can 

 thus understand how it is that the roots are so poorly 

 developed. These usually consist of only two or three 

 slightly divided branches, from one-half to one inch in 

 length, furnished with absorbent hairs. It appears, there- 

 fore, that the roots serve only to imbibe water, though 

 no doubt they would absorb nutritious matter if present 

 in the soil ; for, as we shall hereafter see, they absorb 

 a weak solution _of carbonate of ammonia. A plant of 

 Drosera, with the edges of its leaves curled inward so 

 as to' form a temporary stomach, with the glands of the 

 closely inflected tentacles pouring forth their acid secre' 



