NATURAL HISTORY OF BRITISH SALMONID^E. 135 



which eats fish \ It does not appear to have been clearly 

 proved that this piscivorous plant is usually, or indeed often, in 

 the habit of eating young salmon, and happily its natural pro- 

 clivities seem to favour stagnant rather than running waters ; 

 but as regards the minute fry of other species it has been un- 

 doubtedly caught in flagrante delicto^ with the victims in its 

 stomach, or rather bladder, and therefore it would be rash to 

 assume that its depredations are confined to the fry of the 

 coarser kinds of fish. At any rate the notion of an English 

 fish-eating plant is so novel that I shall probably be pardoned 

 if I take the liberty of here quoting a very interesting account 

 of it which appeared in the ' Pall Mall Gazette ' from the pen of 

 Mr. Grant Allen : 



Our common bladderwort is a small floating water weed, found 

 here and there over all parts of England in still pools and stagnant 

 backwaters, and its long and slender root-like brandies hang on 

 the surface of its favourite ditches in thick masses of tangled vege- 

 tation. It seldom exceeds a foot in length, and has no height at 

 all to speak of, the branches all dispersing themselves radially 

 through the water on every side ; while the flower stems, which 

 alone rise above the surface with their graceful little cluster of 

 snapdragon-like yellow blossoms, hardly attain a greater height 

 than six or eight inches. The tiny leaves, like those of almost all 

 water plants, are very fine and almost hair-like ; but interspersed 

 among them on the branches every here and there are a number 

 of curious small green vesicles or bladders, which give the plant 

 both its common English name of bladderwort and its scientific 

 synonym, Utricularia. These bladders, though submerged, were 

 held to be full of air ; and it was long supposed that their only 

 office was to aid in keeping the plant afloat a belief all the more 

 reasonable because many aquatic plants actually have such air 

 receptacles on their leaves or leaf stalks for that very purpose, as 

 in some familiar seaweeds, and in that curious floating pond plant, 

 the water caltrop of Southern Europe. 



The bladders of the bladderwort, however, differ from these 

 mere floats or swim-bladders of other water plants in the strange 

 peculiarity that they have each a door, closed by a valve which 

 opens inwards only. The whole mechanism, in fact, may be 

 roughly compared to an eel buck or a lobster pot, or even better, 



