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Wolf Spike-rush (Eleocharis wolfii)

Life history

Species overview

Wolf Spike-rush (Eleocharis wolfii), a Wisconsin Endangered and Federal Species of Concern plant, is found on muddy drying bottoms of fluctuating lakes, as well as marshes, and places with wet open sandy acidic soils. Blooming occurs late June through late July; fruiting occurs late July through late August. The optimal identification period for this species is late July through late August.

Synonyms: Scirpus wolfii


  • Distinguishing characteristics: Stems flattened, 1 to 1.5 mm wide when fresh.
  • Flower characteristics: Spikelets narrowly ovate, 4 to 10 mm long and 2 to 3 mm wide, wider than stem; bristles absent; style 3-parted.
  • Fruit characteristics: Achenes gray, roughly round in section, about 1 mm long; tubercle cone-shaped, constricted at base where joins achene.
  • Leaf characteristics: Stems flattened, 2-edged, often twisted, 1-3 dm long and 1-2 mm wide; sheaths often purple at base, membranous at tip.


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


  • Growth form: Graminoid
  • Vegetative reproduction: Rhizomatous
  • Life cycle: Perennial
  • Comments: Associated Species: Aletris farinosa, Xyris sp., Viola lanceolata, Spiraea tomentosa, Rhynchospora capitellata, Juncus spp.

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 Wolf Spike-rush (Eleocharis wolfii). 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 Eleocharis wolfii in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusEND
Federal Status in WisconsinSOC
State RankS1
Global RankG3G5
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 muddy drying bottoms of fluctuating lakes, as well as marshes, and places with wet open sandy acidic soils.
  • Soils: Wet, sandy, acidic soils.

Natural communities

This table lists the natural communities that are associated with Wolf Spike-rush. 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
Southern Sedge Meadow 2
Coastal Plain Marsh 3
Inland Beach 3

Ecological landscapes

This table lists the ecological landscape association scores for Wolf Spike-rush. 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
Central Sand Plains 2
Northern Lake Michigan Coastal 2

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 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

  • Minimize disturbance to hydrology, including soil disturbance from rutting.
  • Avoid disturbance to shorelines and the forest-beach interface.
  • 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.
  • Maintain and restore open habitat through selective clearing and brushing.


Wolf Spike-rush Photo.

Photo ©  USDA-NRCS.

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