Native Freshwater Plants

Bladderworts - Carnivorous Species

The bladderworts received this name because of tiny bladder-like structures on their branched underwater leaves. (The wort part of the name comes from old English, when wort meant plant). These bladders are actually small vacuum traps which catch tiny aquatic animals. The tiny traps are oval, with a membranous door at one end. Small trigger- hairs surround the door that secretes a sweet lure. When an animal comes near the hairs, the door snaps open in a fraction of a second, sucking the animal inside the bladder. Once trapped inside, the plant absorbs the animal’s nutrients using digestive juices. Due to their ability to ‘eat’ animals, bladderworts can live in nutrient poor, rather acidic, boggy conditions. However, they are also common in soft water lakes throughout Washington. Bladderworts are free-floating plants, but usually go unnoticed due to their habit of hanging out near the bottom in shallow areas. They usually attract attention in spring and summer when they float to the surface to send up shoots of small, attractive, yellow snapdragon like flowers.

The scientific name for the bladderworts is Utricularia. A few species are native to Washington, the two most common being Utricularia vulgaris or common bladderwort, and Utricularia minor or lesser bladderwort. One species, Utricularia inflata or big floating bladderwort, appears to be a relatively recent introduction. The first sighting was from Horseshoe Lake, Kitsap County in 1980 – probably the result of a discarded aquarium. Since then this plant has been found in several other lakes in the southern Puget Sound region. When big floating bladderwort is flowering it is easily distinguished from its native cousins by large spoke-like floats that radiate out from the base of the flower stalk. During the rest of the year, however, it can be confused with common bladderwort, both of which are rather robust and can appear almost bushy underwater.