Asplenium scolopendrium var. americanum
Hart's-tongue fern
Image of Asplenium scolopendrium var. americanum

Photo by Michael R. Penskar 

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Key Characteristics

Fern found on large moss-covered dolomite boulders of the eastern Upper Peninsula; frond elongated (20-40 cm) with acute tip, unthoothed, strongly lobed at base.

Status and Rank

  • State Status: E
  • US Status: LT
  • State Rank: S1
  • Global Rank: G4T3


County NameNumber of OccurrencesYear Last Observed
Distribution map for Asplenium scolopendrium var. americanum

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.


This fern is exclusively found on large moss-covered boulders in northern hardwoods in the eastern Upper Peninsula. Usually it is found at or above the 800 ft contour line in Niagara Escarpment region.

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

Fragile fern, green spleenwort, walking fern, maidenhair spleenwort, herb Robert, Braun's Christmas fern, common polypody fern, northern holly fern, sugar maple, Eastern hemlock, beech, yellow birch, basswood, white pine, red oak, white cedar, white birch, ironwood, American elm, balsam fir, white baneberry, red baneberry, wild leek, wild sarsaparilla, jack-in-the-pulpit, blue cohosh, enchanter's nightshade, bunchberry, blue-bead lily, Canada mayflower, Solomon's seal, false spikenard, twisted stalk, bellwort, star flower, nodding trillium, common trillium, maiden hair fern, lady fern, rattlesnake fern, spinulose woodfern, stiff clubmoss, shining clubmoss, ground pine, striped maple, leatherwood, fly honeysuckle, and maple-leaf viburnum.


Generally requires shade and moist, moss-covered limestone or dolomite boulders. Species is likely sensitive to drying and scorching from overexposure to sunlight. Maintain overstory and minimize development and fragmentation. When possible, leave large tracts of unharvested forests and allow natural processes (growth, senescence, wind throw, fire, disease, insect infestation, etc) to operate unhindered. If forest is being managed for timber, minimize fragmentation, leave long periods of recuperation between harvests (50-70 yrs.), preserve as much area as possible in a forested matrix, and maintain a range of canopy closure comparable to pre-harvest closure.

General Survey Guidelines

Random meander search covers areas that appear likely to have rare taxa, based on habitat and the judgement of the investigator. A systematic survey follows transects as a guide to provide the greatest coverage possible of the area. Greatest coverage occurs with parallel transects spaced equidistant over the area.

Survey Methods

Page Citation

Michigan Natural Features Inventory. 2007. Rare Species Explorer (Web Application). Available online at [Accessed Aug 18, 2018]

More Information

See MNFI Species Abstract


Survey References

Technical References

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