Eleocharis radicans
Spike rush

Key Characteristics

Small mat-forming spike-rush (10 cm) of bogs; culms very soft and spongy, topped by small spikelets (2-3 mm) with pale brown scales; achenes very elongated, brown, with small pyramidal cap.

Status and Rank

  • State Status: X
  • State Rank: S1
  • Global Rank: G5


County NameNumber of OccurrencesYear Last Observed
Distribution map for Eleocharis radicans

Updated 5/15/2018. Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.


The Washtenaw locality where this spike-rush was collected is a sedge-sphagnum bog with a floating mat surrounding open water. There are no other Michigan data on habitat. Elsewhere this species occurs in wet sands and mucks, marshy pond and lakeshores, and often grows in floating mats. It was last documented in Michigan in 1930.

Natural Community Types


For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.

Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.

Associated Plants

Sedges (Carex species, probably including C. lasiocarpa), sphagnum moss, and spike-rush (Eleocharis olivacea).


If found, it would likely require conservation of habitat and natural hydrological regime. Likely susceptible to invasive species, particularly purple loosestrife and glossy buckthorn.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgement of the investigator.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at http://mnfi.anr.msu.edu/explorer [Accessed Aug 18, 2018]


Survey References

Technical References

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