PLANT: Bladderwort at Leighton Moss, Lancashire

August 7, 2010:
Common Bladderwort (Utricularia vulgaris s.l.) is flowering now in some of the fen pools at Leighton Moss Reserve. Bladderworts are very sophisticated aquatic carnivorous plants. They comprise an underwater structure of roots and leaves in the form of long stolons to which small bladders are attached by thin stalks whilst the bright yellow flowers project above the water surface on leafless stems. When flowering en masse as at present, they make a spectacular sight and can be seen from one or two places along the causeway there.





The bladders themselves are active traps in which small organisms such as larvae and water fleas are caught and later ingested by the plant. Each bladder comprises a vacuum possessing a negative pressure so that when small amounts of animal matter brush against its sensitive trigger hairs a trapdoor in the bladder opens and the prey, together with its enveloping water, is sucked inside. The trap then closes within a few milliseconds and dissolution of the prey by digestive secretions begins. A similar species, U. minor, is found in more acidic waters in Cumbria and elsewhere. Bladderworts are members of the Lentibulariaceae family to which the terrestrial Butterworts also belong.