Plants and Animals

Juncus dichotomus Forked rush

Key Characteristics

Perennial rush of wetlands, less than 40 cm tall with ridged stem; leaves basal, mostly involute (i.e., rolled-in) without hard cross-partitions; auricle margin thin, translucent, less than 0.6 mm long. inflorescence terminal; flowers attached singly. Auricle characteristics are critical to differentiate from the similar path rush (J. tenuis) and Dudley’s rush (J. dudleyi) which differ in combinations of auricle thickness and length.

Status and Rank

US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5 - Secure
State Rank: SNR - Not ranked

Occurrences

CountyNumber of OccurrencesYear Last Observed
Allegan 1 2017
Bay 1 1927
Berrien 1 1981
Clare 1 1964
Kalamazoo 1 1937
Livingston 1 1962
Midland 1 1927
Saginaw 1 1927
Washtenaw 1 1962

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

Primarily occurs along the Atlantic coastal plain in the southeastern United States but this species has a discontinuous distribution in the southwestern Lower Peninsula of Michigan. Usually found in sandy, acidic, well-drained but wet soils, like sandy meadows and shores. Has been found in brackish areas in other parts of its range.

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

Colic root (Aletris farinose), common ragweed (Ambrosia artemisiifolia), big bluestem (Andropogon gerardii), blue-joint grass (Calamagrostis canadensis), three-ribbed spike-rush (Eleocharis tricostata), round-headed rush (Juncus scirpoides), marsh blazing star (Liatris spicata), switchgrass (Panicum virgatum), white oak (Quercus alba), black oak (Q. velutina), and prairie cordgrass (Spartina pectinata).

Management Recommendations

Possibly overlooked species that needs a status survey in southwestern Michigan. This species requires conservation of habitat and regional and local protection of the hydrology. When occurring in a marsh or depression within or surrounded by fire-dependent natural communities, prescribed burn management can stimulate seed germination and flowering, reduce woody encroachment to maintain open habitat, and maintain a diverse seed bank. This species is also vulnerable to off-road vehicle impacts and dredging and filling activities.

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 first week of July to first week of September

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

  • Bingham, M.T. 1945. The Flora of Oakland County, Michigan. Cranbrook Institute of Science, Bloomfield Hills, Michigan, USA. 155 pp.
  • Elam, C.E., J.M. Stucky, T.R. Wentworth, and J.D. Gregory. 2009. Vascular Flora, Plant Communities, and Soils of a Significant Natural Area in the Middle Atlantic Coastal Plain (Craven County, North Carolina). Castanea 74: 53–77.
  • Graves, C.B., E.H. Eames, C.H. Bissell, L. Andrews, E.B. Harger, and C.A. Weatherby. 1910. Catalogue of the flowering plants and ferns of Connecticut growing without cultivation. State Geological and Natural History Survey, Hartford, Connecticut, USA. 569 pp.
  • Mckenna, D.D. 2004. Flora and vegetation of Kalamazoo County, Michigan. The Michigan Botanist 43: 137–359.
  • Pepoon, H.S. 1927. An annotated flora of the Chicago area, with maps and many illustrations from photographs of topographic and plant features. R Donnelley & Sons Co., Chicago, Illinois, USA. 554 pp.
  • Tiner, R.W. 1985. Wetlands of New Jersey. US Fish and Wildlife Service, National Wetlands Inventory, Newton Corner, Massachusetts, USA. 117 pp.
  • Voss, E.G., and A.A. Reznicek. 2012. Field Manual of Michigan Flora. University of Michigan Press, Ann Arbor, MI. 1008 pp.