Eleocharis microcarpa
Small-fruited spike-rush

Key Characteristics

Small annual spike-rush (30 cm) of coastal plain marshes; culms clumped, leaf sheaths angled at the summit; achenes small and white, with a tiny cap; bristles arising from base of achene short and white.

Status and Rank

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

Occurrences

County NameNumber of OccurrencesYear Last Observed
Allegan11988
Newaygo12006
Distribution map for Eleocharis microcarpa

Updated 1/31/2017. 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.

Habitat

Originally only known in the Allegan State Game Area from one site, this species was recently discovered in Newaygo County. It is found in intermittent, seasonal wetlands with a fluctuating water table and acidic sandy-peaty substrates.

Natural Community Types

Methodology

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

Numerous graminoids associated with coastal plain marshes, bluejoint grass, twig-rush, sedges, bushy aster, black-fruited spike-rush, umbrella-grass, northern clubmoss, panic grass, cross-leaved milkwort, bald rush, tall beak-rush, tooth-cup, netted nut-rush, hyssop hedge nettle, marsh St John's-wort, pipewort, autumn sedge, meadow beauty; shrub margin: red maple, black gum, pin oak, black chokecherry, dogwoods, buttonbush.

Management

This species requires conservation of habitat and protection of the hydrology, including maintenance of cyclical drawdown regime and water table. Maintain moist, open habitat. It is also vulnerable to ORV impacts and dredging and filling activities.

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 Jun 27, 2017]

References

Survey References

Technical References

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