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Ravenfoot Sedge (Carex crus-corvi)

Life history

Species overview

Ravenfoot Sedge (Carex crus-corvi), a Wisconsin Endangered plant, is found along ephemeral woodland ponds. Blooming occurs throughout June; fruiting occurs throughout July. The optimal identification period for this species is late June through early July.

Synonyms: Carex bayardii


  • Distinguishing characteristics: Cespitose; perigynia 6 to 8 mm long with broad spongy base and prominent beak at least twice as long as the body of the perigynium; front of leaf sheath smooth and dotted with red.
  • Flower characteristics: Inflorescences densely spicate, cylindric, elongate, with 15 to 25 distinguishable branches.
  • Fruit characteristics: Perigynia pale brown, red-brown distally, 10 to 12 veined abaxially, 5-veined adaxially; beak to 4.5 mm, mouth deeper abaxially, serrulate, apical teeth somewhat spreading; achenes ovate.
  • Leaf characteristics: Sheaths all with blades, fronts smooth, red spotted, indistinctly linearly veined, apex red-brown, membranous, truncate, minutely ciliate; blades glaucous, not epistomic.


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


  • Growth form: Graminoid
  • Vegetative reproduction: Rhizomatous
  • Life cycle: Perennial
  • Section: Vulpinae
  • Comments: Associated Species: Fraxinus pennsylvanica, Acer rubrum, A. saccharinum, Ulmus americana, Ranunculus flabellaris, Penthorum sedoides, Glyceria grandis, Carex lupuliformis, C. tuckermanii.

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 Ravenfoot Sedge (Carex crus-corvi). 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 Carex crus-corvi 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 along ephemeral woodland ponds.
  • Soils: Moist soils.

Natural communities

This table lists the natural communities that are associated with Ravenfoot Sedge. 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
Ephemeral Pond 2
Southern Hardwood Swamp 2

Ecological landscapes

This table lists the ecological landscape association scores for Ravenfoot Sedge. 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
Southern Lake Michigan Coastal 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 near ephemeral ponds located within a woodland where this species has been observed.
  • Avoid broadcast spraying of herbicides; use care with spot spraying.
  • 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.

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.
  • Minimize disturbance to hydrology, including soil disturbance from rutting.
  • Survey for and control invasive plants prior to conducting timber operations, as these can be spread by vehicles and often respond vigorously to increased light; see forestry BMPs for invasive species.


Ravenfoot Sedge Photo.

Photo by Thomas Meyer, Wisconsin DNR.

Ravenfoot Sedge Photo.

Photo © Robert H. Read.

Ravenfoot Sedge Photo.

Photo © Ken Womble.

Ravenfoot Sedge Photo.

Photo © Robert H. Read.

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