Prenanthes crepidinea
Nodding rattlesnake-root

Key Characteristics

Large, perennial forb of southern floodplain forests; stem ranging from 1-2.5 m, arising from a basal rosette of stalked, coarsely-toothed leaves, with scattered, slightly reduced leaves upward; flowers terminal, with stalked, nodding, flower heads produced in a broad, non-cylindric inflorescence, the flower head bracts (involucre) coarsely hairy.

Status and Rank

  • State Status: T
  • State Rank: SNR
  • Global Rank: G4


County NameNumber of OccurrencesYear Last Observed
Distribution map for Prenanthes crepidinea

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.


Known only from a single occurrence, a floodplain forest in southeastern Lower 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

American elm, hackberry, black maple, wingstem, purple Joe-pye-weed, and garlic mustard.


Little is known about this species in Michigan, but at the present time it is likely best conserved by maintaining floodplain habitat, including the protection of hydrology and seasonal flooding and drawdown cycles, the control of invasive plant species, and preventing the fragmentation of habitat and activities such as excessive timber removal or uncontrolled recreational use.

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 [Accessed Sep 24, 2018]


Survey References

Technical References

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