Bladderwort bladder. Light micrograph of a bladder (round, lower left) from the greater bladderwort plant (Utricularia vulgaris). A smaller bladder is at centre right. This is a carnivorous plant. The bladders trap small aquatic animals, such as water fleas, which then decay into nutrients that are absorbed by the plant. The yellow material surrounding the specimen is the balsam resin that has been used to fix the specimen to the slide. The resin has dried out to form branching patterns around the strands of bladderwort.