Utricularia resupinata

Lavender Bladderwort

Lavender 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"
• resupinata, from the Latin, resupinus, "bent back, thrown back, lying on the back, facing upward, supine"
• Common name from the color of the flower, the distinctive air bladders, and the Anglo-Saxon wort, "plant"
• Also known as Reversed Bladderwort

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: 34463
• Also known as Lecticula resupinata

Description:

• Annual or perennial aquatic herb of shallow waters and wet soil
• Leaves alternate, three-part, to 1¼" long; center segment linear, erect; lateral segments slender, root-like, bearing the bladders.
• Bladders small, deflated, pear-shaped pouches on lateral segments of three-part leaves. 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 delicate, creeping on the surface of shallow waters or just under the surface of wet soils.
• Roots absent
• Flowers single, small, purple, ¼"-½" long, upward facing atop upright stalk, ¾"-4" tall; bract surrounds stalk as a tube; lower lip tri-lobed, spur more-or-less horizontal.
• Sepals 2-5
• Petals 5, united to form upper and lower lips
• Stamens 2
• Ovary superior (within blossom)
• Fruit a rounded, single chamber 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:
  • Single, lavender/purple flower
  • Three-part leaves with bladders on the side segments but not the center.

Distribution:

• Nova Scotia to New York, northern Minnesota and southwest Ontario. Locally found south as far as Florida and Georgia.
• Uncommon in northeastern Minnesota and the BWCA; not known from St. Louis County.

Habitat:

• Shallow to deep waters; wet lake and pond shores where sandy or mucky

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:

• A distinctive, if difficult, native for the water garden

Reproduction:

• Sexually by seed
  • Flowers July-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.