Cystopteris laurentiana
Laurentian fragile fern

Key Characteristics

Low arching fern (20-50 cm) of calcareous rocks; blades twice-divided, ovate to elongated, widest above the base; rachis and pinnae axis with occasional gland-tipped hairs.

Status and Rank

  • State Status: SC
  • State Rank: S1S2
  • Global Rank: G3


County NameNumber of OccurrencesYear Last Observed
Distribution map for Cystopteris laurentiana

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.


Found on limestone and dolomite boulders in the Niagaran Escarpment region of the eastern Upper Peninsula and on granite and limestone outcrops in the western Upper Peninsula.

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, walking fern, maidenhair spleenwort, green spleenwort, polypody,and Braun's Christmas fern.


Requires moist to somewhat dry alkaline outcrops, and is likely impacted by excessive removal of overstory.

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 Aug 18, 2018]


Survey References

Technical References

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