Swollen Bladderwort
Utricularia inflata
Washington State Classification
Monitor List
This plant is on the monitor list - it is not a listed noxious weed in Washington.
Quick Reference
Identification
Growth Habit
Swollen bladderwort is a free-floating carnivorous plant. It has long, branched underwater stems and delicate, finely divided leaf-like stem branches. Yellow flowers are snapdragon-like and are emergent on upright stalks suspended by a spoked float. Like native bladderwort species, swollen bladderwort uses ovoid traps, or “bladders,” on its finely divided stems to capture small organisms.
Leaves
The leaves are very finely divided to frilly and have air bladders spread throughout. They range in size from less than 1 inch to around 7 inches.
Flowers
Swollen bladderwort flowers from May to September in the Pacific Northwest. Flowers are bright yellow, to 20 mm (3/4 inch) across, and in clusters of 3 to 14 on upright stalks. The flower stalk is supported by a whorl of 5-10 spongy floating spokes measuring 3-10 cm (1 to 4 inch) long with fine divisions at the tips. The main submersed leafy part of the plant will sometimes break off from the flowering portion below the whorl of floats.
Fruit & Seeds
Seed capsules are 3-6 mm (1/8-1/4 inch) across and globose with a thick, fleshy wall. Seeds are rough and globose with a diameter of ~0.75 mm.
Impact
This plant is on the monitor list - it is not a listed noxious weed in Washington. Please contact its sponsor Wesley Glisson to report locations or for more information.
Ecology & Spread
Habitat
Swollen bladderwort occurs in ponds, lakes, swamps, and ditches, in shallow to deep water. In Washington, this species was first found in 1980 in Horseshoe Lake (Kitsap County). It is presently known in Kitsap, Mason, Thurston, Pierce, and Cowlitz counties.
Spread Mechanisms
Reproduction
Swollen bladderwort reproduces by seed and can also reproduce asexually through fragmentation of the vegetative portion of the plant.
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