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

Identification

• 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.

Phenology

• 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

Other

• 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.

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).

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.

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.

Other resources

Links to additional Ravenfoot Sedge information

Other links related to vascular plants (all exit the DNR website)

• Wisconsin Flora
• NatureServe Explorer
• Atlas of Wisconsin Prairie and Savanna Flora - Wisconsin State Herbarium
• USDA - NRCS Plants Database
• USGS Midwestern Wetland Flora - field office guide to plant species
• eFloras
• Cofrin Center for Biodiversity Herbarium
• Intermountain Herbarium Grasses of North America
• Orchids of Wisconsin

Photos

Click to view a larger version. Please considering donating a photo to the Natural Heritage Conservation Program for educational uses. Photo use