Utricularia gibba

Humped Bladderwort

Humped Bladderwort
Photo Courtesy USDA Plants Database

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

Name:

• Utricularia, from the Latin, utricularius, "the master of a raft floated on bladders"
• gibba, from the Latin, gibbus, "hunched, humped"
• Common name from growth habit on bottom
• Other common names include: Creeping Bladderwort, Conespur Bladderpod, Bublinatka Pluzgierkatá (Slovak)

Taxonomy:

• 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: 34452
• Also known as Utricularia biflora, Utricularia fibrosa, Utricularia obtusa, Utricularia pumila

Description:

• An annual or perennial aquatic herb of shallow waters.
• Leaves alternate, scattered, only about ¼" long. Carnivorous bladders are attached along the thread-like leaf segments, trapping and digesting tiny aquatic invertebrates.
• Bladders small, deflated, pear-shaped pouches. 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.
• Stems creeping on the bottom in shallow waters, typically less than 4" long, radiating from the base of the flower stalk and forming mats
• Roots absent
• Flowers yellow, perfect, irregular in form, rather resembling a snapdragon; usually 1-3 atop a, 2"-4" stalk. Lips about ¼" long; upper lip of about equal size; spur blunt and shorter than lower lip.
  • Sepals 2-5
  • Petals 5, united to form upper and lower lips
  • Stamens 2
  • Ovary superior (within blossom)
• Fruit a single chamber, rounded capsule, with central column bearing many seeds.

Identification:

• Identifiable as a Bladderwort by its aquatic habitat and distinctive bladders
• Distinguished from other North Country bladderworts by:
  • Bottom-creeping habit
  • Leaves which radiate from the base of the flower stalk

Distribution:

• Quebec to Wisconsin and Minnesota, south to Florida and Louisiana, the Pacific states, Central America, and the West Indies.
• Near the northern extreme of its range in the North Country. Known from St. Louis County but not from Lake or Cook.

Habitat:

• Exposed shores, lakes, ponds, marshes, and fens.

Associates:

• 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.

History:

Uses:

• With the other Bladderworts, a distinctive, if difficult, native for the watergarden.

Reproduction:

• 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

Propagation:

• By seed

Cultivation:

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

Links:

Comments:

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