CARNIVOROUS PLANTS. 



This name has been given to certain 

 plants which have developed the curious 

 habit of capturing insects and using them 

 for food. This behavior seems at first 

 sight most unplantlike, but it is discov- 

 ered that the actual food of all plants is 

 practically the same as that of animals. 

 The chief peculiarity of carnivorous 

 plants, therefore, does not lie in the food 

 which they use, but in the methods which 

 they have worked out for securing it. 



They are all green plants, and hence are 

 able to make food for themselves, but 

 they live in surroundings which are poor 

 in some of the material which they need 

 in the manufacture of food, so that they 

 have learned to supplement their food by 

 capturing insects or other small animals. 

 When it was discovered that these plants 

 not only captured insects, but secreted 

 substances for digesting them, it was 

 thought to be a very astonishing fact. It 

 is found, however, that all plants have di- 

 gestive substances to act upon their food 

 materials, and that animals are not pecu- 

 liar in this regard. It would seem, there- 

 fore, that the use of such food as the 

 bodies of insects and the digesting of this 

 food are not facts which are peculiar to 

 carnivorous plants, but belong to all 

 plants as well. 



It is interesting, however, to observe 

 the various devices which plants have 

 adapted for capturing their prey, and it is 

 these various devices which form the 

 subject of this paper. 



Prominent among the carnivorous 

 plants are the pitcher plants, whose leaves 

 form tubes, or urns, or pitchers of vari- 

 ous forms, which contain water, and to 

 which insects are attracted and drowned. 

 There is a very common pitcher plant in 

 our northern bogs, in whose urn-like 

 leaves insects are found drowned, but 

 which does not have such elaborate ar- 



rangements for their capture as other 

 forms. Perhaps the most famous of the 

 pitcher plants is one which is common 

 throughout the southern states. The 

 leaves are shaped like slender hollow 

 cones, and rise in a tuft from the swampy 

 ground. The mouth of this conical urn 

 is overarched and shaded by a hood in 

 which are translucent spots like small 

 windows. Around the mouth of the urn 

 are glands which secrete a sweet liquid, 

 and drops of this nectar form a trail down 

 the outside of the urn. Inside, just below 

 the rim of the urn, is a glazed zone so 

 smooth that insects cannot walk upon it. 

 Below the glazed zone is another zone 

 thickly set with stiff downward-pointing 

 hairs, and below this is the liquid in the 

 bottom of the urn. If a fly is attracted by 

 the nectar drops on this curious leaf, it 

 naturally follows the trail up to the rim 

 of the urn where the nectar is abundant. 

 If it attempts to descend into the urn it 

 slips on the glazed zone and falls into 

 the water; and if it attempts to escape 

 by crawling up the side of the urn, the 

 thick-set, downward-pointing hairs pre- 

 vent. If it seeks to fly away from the rim 

 it flies towards the translucent spots in 

 the hood, which look like the way of es- 

 cape, as the direction of entrance is in the 

 shadow of the hood. Pounding against 

 the hood the fly falls into the water. This 

 southern pitcher plant is known as a great 

 fly catcher, and is frequently used for this 

 purpose in the south. 



The very largest of the pitcher plants 

 is one which grows in the swamps of Cal- 

 ifornia, whose leaves sometimes become 

 as much as two or three feet high, the 

 huge pitchers forming the most capa- 

 cious receptacle for insects of all kinds 

 and sizes. Its general plan is like that of 

 the southern pitcher plant described 

 above, in that it has an overarching hood 



