PLANTS WITH TRAPS AND PITFALLS TO ENSNARE ANIMALS. 



125 



of cells forming inwardly projecting ridges, and have their sharply-pointed tips 

 directed downwards (see fig. 19 1 ). Amongst these needles are also found, scattered 

 over the whole internal surface, roundish wart-like glands or papilla?, composed of 

 four or eight cells. The bottom of the bladder-like cavity in which the utricle 

 terminates is destitute of bristles, and provided only with glands arranged in rows. 

 Small worms, mites, and other segmented animals which enter through the orifice 

 of the utricle can easily reach the enlarged base. But as soon as they try to com- 



Fig. 20. — Sarracenia purpurea. 



mence the return journey they are opposed by the points of a thousand bristles. 

 Thus caught they die, and the products arising from the decay of their bodies are 

 absorbed by the glands situated, as above mentioned, at the bottom of the bladder 

 and on the walls of the utricle. 



As types of a second series of carnivorous plants belonging to the group of 

 pitcher-plants may be taken Heliamphora nutans, a native of moorlands on the 

 mountains of Roraima, on the borders of British Guiana, and Sarracenia purpurea 

 (see fig. 20), which is widely distributed in the marshes of eastern North America 

 from Hudson's Bay to Florida. In both instances the leaves metamorphosed into 

 ascjdia are arranged in rosettes, rest their bases on damp earth and thence curve 

 upwards. They are somewhat inflated, like bladders, at about their middle, but 

 contract again at the orifice where they pass into the relatively small laminae. 

 The latter are threaded by red streaks like blood-vessels, have the form of valves, 



