Humped Bladderwort

Humped Bladderwort  Utricularia gibba (OBL) also known as U. biflora

The humped bladderwort is a native southeastern carnivorous aquatic plant that flowers from May through September.  The plant was classified as endangered by the MD DNR Natural Heritage Program until 2007, at which time it was de-listed as an uncommon species.  Most all bladderworts are classified as watch-list, rare, threatened or endangered.


The small yellow flower resembles a snapdragon.  Carnivorous bladders attached to thread-like leaf segments trap and digest tiny aquatic invertebrates.  The bladders are small, pear-shaped pouches that open abruptly when trigger hairs are disturbed, sucking in water and any hapless aquatic creature responsible for setting off the trap.


Digestive enzymes and bacteria in the bladder then digest the prey for the nutritional use of the plant, a process typically taking 15 minutes to 2 hours, depending upon the size of the catch.  When digestion is complete, special cells extract the nutrient-rich water from the bladder into the stem, thereby restoring the vacuum and resetting the trap for its next victim.


Bladderworts anchor themselves to submerged water plants.  The plant provides food and shelter for fish and is occasionally eaten by waterfowl.  The water must be rich in microorganisms for the insectivorous bladderwort to survive.


I first observed this species years ago in Prince George’s County, in Cedarville and Beltsville.  I’ve also found the plant in Anne Arundel County, and with today’s sighting in Howard County.  The plant occurs in sunny, exposed and stable fens, bogs, swamps, ponds and lakes.

If I get the opportunity, I’d like to gently pull some plants from the water, rinse off any slime/debris from the roots and then set the plants in a white tray with clean, clear waters and get close-up photos of the bladders.