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Common Butterwort (Pinguicula vulgaris)

Life history

Species overview

Common Butterwort (Pinguicula vulgaris), a Wisconsin Endangered plant, is found on moist ledges and mossy boulders on shaded sandstone cliffs in the Apostle Islands. Blooming occurs early June through early July; fruiting occurs throughout July. The optimal identification period for this species is late June through late July.

Synonyms: Pinguicula vulgaris var. americana


  • Distinguishing characteristics: Very distinctive. There are no other species of this genus in the state. The flowers may appear similar to a violet although the leaves can be used to distinguish the two genera.
  • Flower characteristics: Corolla violet, 1.5 to 2 cm (spur included), 5-lobed, 2-lipped, the lower lip longer than the upper and prolonged into a conspicuous basal spur; calyx 5-lobed, somewhat 2-lipped.
  • Fruit characteristics: Capsule small, 4 to 6 mm long, globose; seeds small.
  • Leaf characteristics: Basal, commonly 3 to 6, ovate to elliptic, 2 to 5 cm long, very obtuse, narrowed to the base, the upper surface sticky.


  • Blooming phenology: early June through early July
  • Fruiting phenology: throughout July
  • Optimum time to identify: The optimal identification period for this species is late June through late July


  • Growth form: Forb-erect
  • Vegetative reproduction:
  • Life cycle: Perennial
  • Comments: Associated Species: Primula mistassinica, Trisetum spicatum, Agrostis hyemalis, Thuja occidentalis, Sorbus decora, Betula papyrifera, Ledum groenlandicum, Carex capillaris, Alnus crispa, Betula papyrifera. Small insects caught on the slimy leaf surface are digested.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Common Butterwort (Pinguicula vulgaris). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Documented locations of Pinguicula vulgaris in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusEND
Federal Status in Wisconsinnone
State RankS1
Global RankG5
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found on moist ledges and mossy boulders on shaded sandstone cliffs in the Apostle Islands.
  • Soils: Wet soils.

Natural communities

This table lists the natural communities that are associated with Common Butterwort. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Natural communities score
Moist Cliff 3

Ecological landscapes

This table lists the ecological landscape association scores for Common Butterwort. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Ecological landscape score
Superior Coastal Plain 3

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • Avoid direct disturbance to sensitive microsites such as seeps, cliffs, and moss-covered boulders.
  • Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
  • Avoid broadcast spraying of herbicides; use care with spot spraying.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Buffer management around unique microhabitats such as ephemeral ponds, seeps, etc.
  • Follow BMPs, especially around streams and use care near ravines, steep slopes, cliffs, rock outcrops, etc.
  • Minimize disturbance to hydrology, including soil disturbance from rutting.


Common Butterwort Photo.

Moist cliff community on Devil's Island with butterwort and bird's eye primrose.

Photo by Christina Isenring, Wisconsin DNR.

Common Butterwort Photo.

In Wisconsin, butterwort is limited to the Superior Coastal Plain, where it inhabits cliffs along Lake Superior.

Photo by Thomas Meyer, Wisconsin DNR.

Common Butterwort Photo.

Photo © John Kohout.

Common Butterwort Photo.

Butterwort is a rare carnivorous plant that reaches its extreme southern range limits on sandstone cliffs on the margins of several of the Apostle Islands.

Photo by  staff, Wisconsin DNR.

Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Wednesday, May 05, 2021
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition