Dichanthelium polyanthes
Round-seed panic-grass

Key Characteristics

Tufted grass of sandy, seasonally inundated wetlands (known also from a swamp border in southeastern Michigan); stems few per clump; cauline leaves 4-7, with cordate bases; inflorescence narrow, more than twice as long as wide, with small (1.5 mm) spherical spikelets.

Status and Rank

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


County NameNumber of OccurrencesYear Last Observed
Distribution map for Dichanthelium polyanthes

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.


Round-seeded panic grass is found in seasonally flooded wetlands formed in shallow depressions and potholes in glacial lakeplain and outwash landscapes. It is known from only a handful of sites in extreme southern Lower Michigan, where it occurs in remnant open wetland habitat with several coastal plain disjunct species. The species has also been documented from the border of a tamarack - red maple swamp in southeastern Michigan.

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

Trail rush, Canada rush, panic grasses, rough goldenrod, ticklegrass, beak-rush, boneset, blue-eyed grass, bluejoint grass, steeplebush, foxglove beard-tongue, and bulrush.


This species is known in Michigan from two markedly different habitats, and little is known about its ecology. Protection of hydrology is important, and periodic prescribed fires may maintain appropriate conditions in its open wetland habitats. Like many plants of sandy shores and moist prairies, it is also probably highly vulnerable to disturbance from ORVs.

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 Sep 24, 2018]

More Information

See MNFI Species Abstract


Survey References

Technical References

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