Mamillate Spike-rush (Eleocharis mamillata)

Life history

Species overview

Mamillate Spike-rush (Eleocharis mamillata), a Wisconsin Special Concern plant, is found on the edge between wet meadow and shrub-carr and on sphagnum-sedge bog mat in Wisconsin. Rangewide, it has been found on fresh lakeshores, shallow ponds, streams, floating mats, bogs, fens, and ditches. Blooming occurs mid-May through late August; fruiting occurs mid-June through late September. The optimal identification period for this species is mid-June through late September.

Synonyms: None

Identification

• Distinguishing characteristics: Often confused with E. palustris and E. macrostachya. They are differentiated by perianth (flower) bristles and achenes.
• Flower characteristics: Perianth (flower) bristles (4-) 5 to 6 (-8), brown, slender to stout, mostly exceeding the tubercles, to twice as long as the achene; stamens 3.
• Fruit characteristics: Achenes not persistent, yellow maturing to straw-colored, biconvex with obscure angles, apex rounded with no neck; tubercles brown to partly white.
• Leaf characteristics: Distal leaf sheaths persistent, often splitting away from the stem, usually reddish close to the stem and turning to straw-colored further from the stem.

Phenology

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

Other

• Growth form: Graminoid
• Vegetative reproduction: Rhizomatous
• Life cycle: Perennial
• Comments: Associated Species: Salix gracilis, Alnus rugosa, Carex lacustris, Cyperus cyperinus.

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 Mamillate Spike-rush (Eleocharis mamillata). 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 on the edge between wet meadow and shrub-carr and on sphagnum-sedge bog mat in Wisconsin. Rangewide, it has been found on fresh lakeshores, shallow ponds, streams, floating mats, bogs, fens, and ditches.
• Soils: Moist to wet soils.

Natural communities

This table lists the natural communities that are associated with Mamillate 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).

Ecological landscapes

This table lists the ecological landscape association scores for Mamillate Spike-rush. 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 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

• Maintain and restore open habitat through selective clearing and brushing.
• Prescribed burns and/or brushing may be beneficial (dependent on local site conditions).
• Minimize disturbance to hydrology, including soil disturbance from rutting.

Other resources

Links to additional Mamillate Spike-rush 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