290 PLANT-LIFE 



The Butterworts {Pinguicula) are also carnivorous. 

 About twenty species are known; they occur in north 

 temperate regions. We have three British species, 

 p. vulgaris (Plate LII.) being particularly common in 

 boggy places. The generic name is from pinguis, fat, 

 and has reference to the greasy texture of the pale green 

 leaves. This plant does not have tentacular leaves, but 

 their surface is sticky, and small flies, which seem to be 

 attracted by them, are captured by a species of " bird- 

 lime " trick. The margins of the leaves roU over a 

 captive, and certain glands secrete a digestive ferment. 

 The leaf forms a sort of bowl, with a recurved rim, in 

 which the insect broth is retained until it is completely 

 absorbed. In Lapland the leaves are used to curdle 

 milk. 



The Bladderworts belong to the same family as the 

 Butterworts (LentibulariacecB) , but are classed in a 

 separate genus, Vtricularia. There are about 150 species, 

 some of which are terrestrial. The aquatic species 

 known in Britain, three in number, are floating plants 

 with much divided leaves, the segments being very 

 slender. The name " Bladderwort " is due to the exist- 

 ence of so-called " bladders " among the leaves. These 

 bladders used to be regarded as floats, but investigation 

 has proved that they are minute traps in which small 

 water animalculae, such as Cyclops, or Water-fleas 

 (Daphnia), are captured. The captives are not treated 

 with a digestive secretion, but are allowed to die in the 

 natural course, and the liquid product of their decay is 

 absorbed by glands that line the inner surface of each 

 bladder. 



Symbiotic plants (Gr. syn, together; bios, life) are 



