Utriculata inflata (swollen bladderwort) is an introduced weed from the eastern US and is in the family Lentibulariaceae (the bladderwort family). Species native to western Washington in this family include U. minor (lesser bl.), U. macrorhiza (greater bl.), U. intermedia (flat-leaved bl.), U. gibba (humped bl.) and Pinguicula macroceras (common butterwort). The Utriculata species are quite easy to tell apart based upon leaf shape and bladder shape and location. All occur in slow moving or standing water. This individual was photographed at Grass Lake in Olympia.
The bladders of this species are photographed below. The valves of the bladders open when prey agitate trigger hairs. Small crustaceans and protozoa are trapped in the bladders and broken down by plant enzymes, providing the plants with nutrients. Most, if not all of the bladderwort species are rootless and occur suspended in the water column with much-reduced, heavily-dissected leaves that would not allow for much photosynthesis (hence it's carnivorous nature).
