Utricularia minor

Lesser Bladderwort

Lesser Bladderwort, Photo Courtesy USDA Plants Database
Lesser Bladderwort
Photo Courtesy USDA Plants Database

Flora, fauna, earth, and sky...
The natural history of the northwoods


  • Utricularia, from the Latin, utricularius, "the master of a raft floated on bladders"
  • minor, from the Latin, "smaller"
  • Common name from its small size in relation to the other Bladderworts
  • Other common names include: Dvärgbläddra, Dvärgblåsört (Swe), Småblærerod (Nor), Liden Blærerod (Dan), Pikkuvesiherne (Fin), Blöðrujurt (Is), Kleiner Wasserschlauch (Ger)


  • Kingdom Plantae, the Plants
    • Division Magnoliophyta, the Angiosperms (flowering plants)
      • Class Magnoliopsida, the Dicotyledons
      • Subclass Asteridae
        • Order Scrophulariales, the
          • Family Lentibulariaceae, the Bladderworts
            • Genus Utricularia, the Bladderworts
  • Taxonomic Serial Number: 34457


  • A perennial aquatic herb of shallow waters and wet soil
  • Leaves alternate, with few divisions; segments slender, flat, smooth edged
  • Bladders small, deflated, pear-shaped pouches; very small (1mm-2mm); 1-5 per leaf. Not air-filled or used for floatation, they 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 vaccuum and resetting the trap for its next victim.
  • Stem creeping along bottom or on wet soil; limited branching; 4"-12" long
  • Roots absent
  • Flowers pale yellow, perfect, irregular in form, rather resembling a snapdragon; usually 2-8 atop a thread-like stalk rising 1½"-6" above the water's surface. Individual flower stalks ¼"-½" and curved downward when in fruit. Lower lip of blossom 4mm-8mm, twice as long as upper; spur quite short (half the length of lower lip).
    • Sepals 2-5
    • Petals 5, united to form upper and lower lips
    • Stamens 2
    • Ovary superior (within blossom) inferior (below flower)
  • Fruit a single chamber capsule, with central column bearing many seeds.


  • Identifiable as a Bladderwort by its aquatic habitat and distinctive bladders
  • Distinguished from other North Country bladderworts by:
    • Bladders borne on leaves
    • Flower spur much shorter than lower lip


  • Circumboreal, south in North America to New Jersey, Indiana, North Dakota, and California.


  • Fens, open bogs, sedge meadows, and marshed; often in shallow water and where calcium-rich.


  • Aquatic: Coontail (Ceratophyllum demersum), Duckweeds (Lemna minor, Lemna trisulca, Spirodela polyrhiza)
  • Mammals: Occasionally eaten by muskrats, but not a preferred food.
  • Birds: Occasionally eaten by ducks and other waterfowl, but not a preferred food.
  • Invertebrates (as prey): Fairy Shrimp (Branchiopoda), Water Fleas (Cladocera), Copepods (Copepoda), Scuds (Amphipoda). Also preys on paramecia, rotifers, nematodes, and microscopic insect larvae.


  • In 1875 it was Charles Darwin himself who, along with two other biologists, finally established that the bladders of the Bladderworts were not for flotation, as had long been assumed, but were instead sophisticated traps for tiny animals.


  • With the other Bladderworts, a distinctive, if difficult, native for the water garden


  • Sexually by seed
    • Flowers June-August
    • Insect pollinated
  • Asexually by turions (winter buds), the most common method
    • Dense, starch-rich leaf masses form at tips of branches in late fall, dropping to the bottom and remaining dormant through the long winter.
    • Turions begin growing as spring water temperatures rise, absorbing air in their leaves to become buoyant.


  • By seed


  • Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)
  • Not generally available commercially.



  • The bladderworts are the only predatory aquatic plants in the US.

Valley Internet Company
Return to Home Page
Send Feedback to Webmaster

Last updated on 26 February, 2004