Plants and Animals

Eleocharis geniculata Spike-rush

Key Characteristics

A relatively small, annual spike-rush of marshy lakeshores and low ground; forming tufts with erect to spreading, delicate stems 0.5 mm thick or less, ranging from 3-20 cm, achenes 2-sided and styles 2-cleft, summit of leaf sheaths not split, with shiny, dark, purplish achenes not over 1 mm long including the tiny tubercle

Status and Rank

US Status:
State Status: X - Presumed extirpated (legally 'threatened' if rediscovered)
Global Rank: G5 - Secure
State Rank: SX - Presumed extirpated

Occurrences

CountyNumber of OccurrencesYear Last Observed
Jackson11937
Washtenaw21936

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

Typically found along marshy, alkaline lakeshores, and in low ground with fen associates.

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

No associate data are known for the three historical state sites for this species. According to Swink and Wilhelm (1994), the species is no longer extant in the Chicago area, but persists in nearby areas in Indiana, where the typical associates include nut-sedge, spike-rush, rush, Canada rush, Kalm's lobelia, common water-horehound, beak-rush, and arrow-grass.

Management Recommendations

Protect habitat from direct destruction, excessive use of herbicides, and competitive exotic species such as purple loosestrife. Non-point source pollution, such as nutrient enrichment, that pollutes aquatic environments and degrades water quality is also likely detrimental to this species.

Survey Methods

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

  • Meander search

    • Survey Period: From third week of August to fourth week of October

References

Survey References

  • Elzinga, C.L., D.W. Salzer, and J.W. Willoughby. 1998. Measuring and Monitoring Plant Populations. The Nature Conservancy and Bureau of Land Management, Denver. BLM Technical Reference 1730-1. 477pp.
  • Goff, G.F., G.A. Dawson, and J.J. Rochow. 1982. Site examination for Threatened and Endangered plant species. Environmental Management 6(4): 307-316
  • Nelson, J.R. 1984. Rare Plant Field Survey Guidelines. In: J.P. Smith and R. York. Inventory of rare and endangered vascular plants of California. 3rd Ed. California Native Plant Society, Berkeley. 174pp.
  • Nelson, J.R. 1986. Rare Plant Surveys: Techniques For Impact Assessment. Natural Areas Journal 5(3):18-30.
  • Nelson, J.R. 1987. Rare Plant Surveys: Techniques for Impact Assessment. In: Conservation and management of rare and endangered plants. Ed. T.S. Elias. California Native Plant Society, Sacramento. 8pp.

Technical References

  • Flora of North America Editorial Committee. 2002. Flora of North America, North of Mexico. Volume 23: Magnoliaphyta: Commelinidae (in part): Cyperaceae. Oxford University Press, New York. 608pp.
  • Gleason, H. A., and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. Second edition. The New York Botanical Garden, Bronx. 910pp.
  • Godfrey, R.K. and Wooten. 1979. Aquatic and Wetland Plants of Southeastern United States. Monocotyledons. University of Georgia Press, Athens. 933pp.
  • Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the vascular plants of Northeastern United States and adjacent Canada. New York Botanical Garden, Bronx. 937pp.
  • Rothrock, P.E. 2009 Sedges of Indiana and the Adjacent States, The Non-Carex Species. Indiana Academy of Science, Indianapolis, IN. 270 pp.
  • Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region, 4th ed. Indiana Academy of Science, Indianapolis. 921pp.
  • Voss, E. G. 1972. Michigan Flora. Part I. Gymnosperms and Monocots. Bulletin of the Cranbrook Institute of Science and University of Michigan Herbarium. 488pp.