Pycnanthemum verticillatum
Whorled mountain mint
Image of Pycnanthemum verticillatum

Photo by Ryan P. O'Connor 

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Key Characteristics

Tall forb (1 m) of moist shores and meadows; stems densely pubescent; minty-aromatic leaves sessile and lanceolate, more than 3 times long as wide, pubescent only on the veins on the undersurface; flowers white, borne in dense terminal clusters.

Status and Rank

  • State Status: SC
  • State Rank: S2
  • Global Rank: G5

Occurrences

County NameNumber of OccurrencesYear Last Observed
Allegan42014
Berrien31985
Huron21951
Muskegon32006
Newaygo32005
Ottawa11910
Van Buren11983
Distribution map for Pycnanthemum verticillatum

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

Whorled mountain-mint is found in seasonally flooded wetlands formed in shallow depressions and potholes in glacial lakeplain and outwash landscapes.

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, including Engelmann's spikerush, panic grasses, meadow beauty, autumn-grass, blue-eyed-grass, lance-leaved violet, and bulrushes.

Management

The species requires conservation and protection of hydrology of intermittent wetlands. It is also vulnerable to ORV impacts and dredging and filling of sites.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgment 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 29, 2017]

More Information

See MNFI Species Abstract

References

Survey References

Technical References

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