The bladderworts are insectivorous, aquatic plants. The bladders scattered among the leaves serve two purposes - to float the plant at time of flowering and to entrap minute water-animal food.
In U. vulgaris the bladders are large. They are furnished with a hinged lid, and with hairs turning inward, so as to prevent the escape of a larva which may have ventured within the mouth of the bladder. It is said that the hairs keep up a wavy motion and so create a sort of current which sucks the creature in if it ventures near these traps.
The bright yellow blossom, coming to the water's surface on a scape 1/3 foot long, has a 2-lipped corolla, like some of the figworts. The leaves are very much dissected, and when first pulled up hang stringily together. Take this unpromising plant home, place it in a basin of water, pick off the mud and slime that cling to it, and you have a beautiful botanical specimen. Slip the pressing-paper under while in the water, and dry with several thicknesses of paper.
U. subulata is a very small species. A short scape, 3 or 4 inches high, bears yellow blossoms, half a dozen or so, on hair - like pedicels. The leaves are grass-like, not dissected.
U. inflkta. - In this species the otherwise naked flower-stalk bears, about the middle, a whorl of 5 to 9 leaves whose petioles are swollen and bladder-like, tipped with finely dissected leaf-blades, 1 to 2 inches long. These are very strange looking leaves, but the swollen petioles, with bladders plentifully interspersed, make the plant float freely and bring the flowers to the top. Lower leaves finely dissected, bearing small bladders. Upper lip of corolla large, helmet - shaped. Flowers, 3 to 10, in irregular racemes at ends of branches. July to September.
In ponds, coves, and still water from Maine to Texas, near the coast. I have found this bright - flowered species in Greenwood Lake, New Jersey, near the shore, its yellow flowers dotting the surface of the water.