74 BOTANY. [CHAP. 11. 



used, because the members of the animal kingdom 

 captured by plants are usually insects. 



This peculiar carnivorous propensity exhibited by 

 certain plants does not appear to have been possessed 

 by such for all time, but must rather be looked upon 

 as an acquired character. The evidence in favour of 

 this idea is the fact that carnivorous plants occur belong- 

 ing to widely separated families of plants, and, further, 

 that every phase of differentiation in the development 

 of those characters that enable a plant to benefit by a 

 carnivorous habit is met with in the various members 

 included under this heading. 



Carnivorous plants are generally inhabitants of swamps 

 or marshy places as the sundews (Drosera), butterworts 

 (Pinguicula) , pitcher plants (Nepenthes), etc., others, as 

 the bladderwort ( Utricularia) , are aquatic. Most agree 

 in having imperfectly developed roots or in being en- 

 tirely rootless. The leaves of carnivorous plants, either 

 entirely or in part, are the portions modified for the 

 purpose of capturing insects. In some kinds, as the 

 sundews, the leaves are sensitive and close round the 

 insect alighting on the upper surface which is furnished 

 with glands that secrete an acid and a substance closely 

 resembling pepsine ; these secretions, which closely re- 

 semble in composition and function gastric juice, act on 

 the body of the insect, and a true process of diges- 

 tion, similar to what occurs in the stomach of an animal, 

 takes pi ace, in fact, the leaf when curled up and digesting 

 an insect may be compared to an extemporized stomach. 

 The leaves of our common sundews are bright red on the 

 upper surface, possibly for the purpose of attracting 

 insects, and are furnished round the margin with a row 



