CA BNI VORO US PLANTS 



351 



' palate ' ; two stamens ; and a one-celled ovary that ripens into a 

 globular fruit. 



As to the little air-bladders mentioned above, they form, per- 

 haps, the most interesting featvu'e of the plant, for they are the 

 traps by means of which small aquatic creatures are caught, and also 

 the organs concerned in the absorption of nutritive products 

 derived from the prey. Each bladder has an opening, guarded by a 

 kind of valve wliich allows easy ingress, but no exit. It does not 

 seem to produce any secretion which would hasten the death of 

 the creatures entrapped, nor does 

 it appear to produce any kind of 

 digestive fluid, as is the case with 

 other carnivoi'ous plants ; but small 

 aquatic creatures, such as water- 

 fleas, Cyclops, very small larvae, 

 &c., entering the bladders for shelter 

 or some other purpose, are securely 

 imprisoned until they die of starva- 

 tion or suffocation ; and their bodies 

 then decay, giving rise to soluble 

 gases and other products which are 

 absorbed into the plant by special 

 cells within the bladder. 



There are three British species of 

 these plants — the Greater, the Lesser, 

 and the Intermediate Bladder-worts. 

 The first of these — Ulricidaria vul- 

 garis — is rather local in its dis- 

 tribution, and is easily distinguished 

 from the other two by its superior 



size, having floating branches from a few inches to a foot in length. 

 The second ( U. minor) is much more common. Its floating branches 

 are only two or three inches long at the time of flowering, but 

 they grow longer after ; and the flowers are pale yellow, with a 

 short, broad spm-. The thii'd {U. intermedia), which is very local, 

 has also pale yellow flowers, but with a much longer spur; and 

 the bladders are at the ends of leafless branches. 



In the preceding chapter we gave an account of certain plants 

 which are parasitic on other plants and trees, deriving more or less 

 of their nutriment from their vegetable hosts. One of these — the 

 Tooth-wort {Lathroia squamaria), of the order Orohancharece — 



THE Greater Bladder-wort. 



