Plants That Feed on Insects. 25 



only can live. Although the leaves of the Droseras at a 

 hasty glance do not appear green, owing to the purple color 

 of the tentacles, yet the superior and inferior surfaces of the 

 blade, the stalks of the central tentacles, and the petioles 

 contain chlorophyll, rendering the best of evidence that the 

 plants obtain and assimilate carbon dioxide from the air. 

 But when the poverty of the soil where these plants grow is 

 considered, it is at once apparent that their supply of nitrogen 

 would be exceedingly small, or quite deficient, unless they 

 had the power of obtaining it from some other source. From 

 captured insects this important element is largely obtained, 

 and thus we are prepared to understand how it is that their 

 roots, which consist of only two or three slightly divided 

 branches, from one-half to one inch in length, and furnished 



ROUND-LEAVED SUNDEW. 

 Leaves Acting as Stomachs. 



