Utricularia purpurea (Purple-flowered Bladderwort)

Plant Info
Also known as:
Family:Lentibulariaceae (Bladderwort)
Life cycle:perennial
  • State Endangered
Habitat:sun; lakes, usually in shallower water near a boggy shoreline
Bloom season:July - September
Plant height:1 to 6 inches
Wetland Indicator Status:GP: none MW: OBL NCNE: OBL
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

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Detailed Information

Flower: Flower shape: irregular Cluster type: raceme

[photo of flowers (not fully open)] Raceme bearing 1 to 4 pinkish-purple, snapdragon-like flowers at the top of a naked maroon stem emerging 2 to 5 inches out of the water. Flowers are 1/3 to ½ inch long, the lower lip when fully extended is 3-lobed, white at the base with a spot of yellow in the center. The upper lip is rather shorter than but nearly as wide as the lower lip. A curved spur is present below the lower lip that is yellowish to white and shorter than the lower lip.

Leaves and stems: Leaf attachment: whorl Leaf type: simple

[photo of leaves with bladders] Stems and leaves are submerged and free-floating. Roots do not develop. Leaves occur in whorls of 5 to 7 with bladders at the tips of leaves. Turions (overwintering vegetative buds) develop on branch tips in the early fall. Stems may grow to 3 feet long.

Fruit: Fruit type: capsule/pod

Fruit is a round capsule.


Purple-flowered Bladderwort is the rarest Utricularia in Minnesota. According to the DNR, it was first observed in 1992 and has since only been located in fewer than a dozen lakes. It was listed as a Special Concern species in 1996 and elevated to Endangered in 2013, the primary threat being development that would alter water chemistry and degrade its aquatic habitat. When in bloom it could only be confused with Lavender Bladderwort (Utricularia resupinata), our other purple-flowered Bladderwort, but U. purpurea can easily be distinguished from all other Utricularia species in Minnesota by its whorled leaves and bladders at the leaf tips. Although the commonly held view is that the bladders of bladderworts are for capturing and digesting microorganisms that provide the plant with nutrients, bladders more often have been observed to contain communities of microorganisms (bacteria, algae, and diatoms) living in the bladders, not as prey, suggesting that the bladders may also, and perhaps more importantly, serve to establish mutually beneficial relationships with some microorganisms.

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More photos

Photos courtesy Peter M. Dziuk taken in Pine County.


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