PROTECTING WISCONSIN'S BIODIVERSITY

 
 
   
 
Scientific Name Common Name Global Rank State Rank Federal Status WI Status

Flat-stemmed Spike-rush (Eleocharis compressa var. compressa)

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Photo by Ryan O'Connor

 

Counties with Mapped NHI Occurrences

Flat-stemmed Spike-rush (Eleocharis compressa var. compressa), a Wisconsin Special Concern plant, is found in moist to wet, often calcareous prairies and mud flats. Blooming occurs early-May through early-June, fruiting late-June through late-July. The optimal identification period for this species is late-June through July.

 
 
 

Flat-stemmed spike-rush is a graminoid with flower heads that are a single spikelet at tip of stem, flowers are perfect, sepals and petals are absent or reduced to 1-5 bristles, spikelets are ovate, 4-10mm long and 3-4 mm wide. Its fruits are yellow-brown achenes covered with small bumps, and somewhat 3-angled. Tubercles are small and constricted at base. Its stems are flattened and often twisted and shallowly grooved. Sheaths are red or purple at base.

It is readily distinguished from other Eleocharis species by its flattened stems with 9-14 vascular bundles.

Rhizomatous. Blooming occurs early-May through early-June, fruiting late-June through late-July.

Perennial. The optimal identification period for this species is late-June through late-July.

Associated species include Andropogon gerardii, Galium obtusum, Lobelia spicata, Rudbeckia hirta, Senecio plattensis, Sorghastrum nutans, and Helianthus species.

Flat-stemmed spike-rush is found in moist to wet, often calcareous prairies and mud flats.

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 and use care with spot spraying.

Prescribed burns and/or brushing may be beneficial, dependent on local site conditions and burn frequency. Rotational burns with annual unburned refugia may be preferred.

Minimize disturbance to hydrology, including soil disturbance from rutting.

Maintain and restore open habitat through selective clearing and brushing.

Species of Greatest Conservation Need (SGCN) are associated with habitats (or natural communities) and places on the landscape. Understanding relationships among SGCN, natural communities and ecological landscapes help us make decisions about issues affecting SGCN and their habitat and how to respond. Download the Wildlife Action Plan association score spreadsheet to explore rare species, natural communities and ecological landscape associations

Conservation actions respond to issues or threats, which adversely affect species of greatest conservation need (SGCN) or their habitats. Besides actions such as restoring wetlands or planting resilient tree species in northern communities, research, surveys and monitoring are also among conservation actions described in the Wisconsin Wildlife Action Plan because lack of information can threaten our ability to successfully preserve and care for natural resources.