Utricularia

Utricularia 

(bladderwort), a genus of insectivorous plants of the family Lentibulariaceae. The plants live in water and swamps; some are epiphytes. Bladderworts have no roots owing to their insectivorous mode of feeding and, for many of them, their aquatic life. The leaves are divided into thin threadlike lobes that end in small bladders for trapping small aquatic animals. On the free end of each bladder there is an opening with a valve that only opens inward; bristles are situated along the edge of the opening. Even the slightest pressure on the valve exerted by an animal will cause the valve to open. The insect enters the bladder and is digested there through the action of enzymes secreted by the bladder walls. Aquatic bladderworts flower, and their racemes are above water. Bladderworts develop winter buds, which serve for overwintering. There are approximately 250 species. Of the four species growing in the USSR, the best known are the greater bladderwort (U. vulgaris) and the intermediate bladderwort (U. intermedia). Some species have medicinal value.