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Montana Field Guides

Mountain Moonwort - Botrychium montanum

Potential Species of Concern
Native Species

Global Rank: G3G4
State Rank: S3S4
(see State Rank Reason below)
State Threat Score: Unknown

Agency Status


External Links

State Rank Reason (see State Rank above)
This moonwort species is known from numerous observations in western Montana. Populations are often small and most have been found in old growth Western Red Cedar forest, though some have been documented from second growth forests. Populations occur on a mix of federal, state and private ownerships.

Montana supports a significant percentage of the species range-wide populations.
  • Details on Status Ranking and Review
    Mountain Moonwort (Botrychium montanum) Conservation Status Review
    Review Date = 06/01/2012
    View State Conservation Rank Criteria
    Population Size

    Score1-2 - Small to Moderate. Population size is imprecisely known but is believed to be >2,000 individuals and <100,000 individuals.

    Range Extent

    Score1 - Peripheral, Disjunct or Sporadic Distribution in MT: Widespread species that is peripheral, disjunct or sporadically distributed within MT such that it occurs in <5% of the state (<7,500 sq. miles or the combined area of Beaverhead and Ravalli Counties) or is restricted to 4-5 sub-basins.

    Area of Occupancy

    Score0 - High: Occurs in >25 Subwatersheds (6th Code HUC’s).

    Environmental Specificity

    Score1 - Moderate: Species is restricted to a specific habitat that is more widely distributed or to several restricted habitats and is typically dependent upon relatively unaltered, good-quality habitat (C Values of 5-7).


    Score0-2 - Stable to Moderate Declines:

    CommentActual trends are unknown, though the possibility of severe declines appears to be unlikely.


    Score0-1 - Low to Medium.

    Intrinsic Vulnerability

    Score1 - Moderate Vulnerability: Specific biological attributes, unusual life history characteristics or limited reproductive potential makes the species susceptible to extirpation from stochastic events or other adverse impacts to its habitat and slow to recover.

    Raw Conservation Status Score

    Score 4 to 8 total points scored out of a possible 19.

General Description
Mountain Moonwort is a small perennial fern with a single aboveground frond. The frond varies in height but may reach a height of 12 cm. It is a dull, glaucous gray-green, somewhat succulent, and divided into two segments which share a relatively short common stalk. The sterile segment is once pinnatifid with well separated, irregular, angular, ascending lobes with entire or toothed margins. The fertile segment is longer than the sterile segment, is branched, and bears grape-like sporangia. Spores germinate underground and develop into minute subterranean, non-photosynthetic gametophytes which depend on an endophytic fungus for nourishment.

Fronds mature in July-August.

Diagnostic Characteristics
The glaucous gray-green color, succulent texture, relatively short common stalk, and irregular angular lobes rather than distinct pinnae are diagnostic of B. montanum. Among the moonworts of Montana, B. montanum is relatively easily recognized, but may be mistaken for B. ascendens; also, small plants may be confused with other species. Reliable field determination of moonworts depends on the careful use of technical keys and comparison with sihouette outlines of verified specimens. Identification can be complicated because there is often a high degree of morphological variability between individuals in a population and between populations of the same species; several species may grow together at the same site, and the few diagnostic characters may not be apparent in small plants.

Species Range
Montana Range Range Descriptions


Range Comments
Botrychium montanum is found in western North America, British Columbia, Washington, Oregon, northern California, northern Idaho and northwestern Montana. Most of the known occurrences have been reported from Oregon, Montana, and Washington and to a lesser extent in Idaho, British Columbia and California, where it is known from 1 location.

Observations in Montana Natural Heritage Program Database
Number of Observations: 180

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Usually in deep litter of springy, mature western red cedar forests, but also in riparian thickets, mesic meadows, and grassy trail edges.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see

Ecological Systems Associated with this Species

  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Farrar, Donald. 2011. Moonwort (Botrychium) Systematics. Ada Hayden Herbarium. Iowa State University.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
    • Mantas, M. and R.S. Wirt. 1995. Moonworts of western Montana (Botrychium subgenus Botrychium). Flathead National Forest. 103 pp.
    • Vanderhorst, J.P. 1997. Conservation assessment of sensitive moonworts (Botrychium subgenus Botrychium) on the Kootenai National Forest. Unpublished report. Montana Natural Heritage Program, Helena, MT 82 pp. plus appendices.
    • Wagner, D.H. 1992. Guide to the species of Botrychium in Oregon, November 1992. Unpublished report. USDA Forest Service 19 pp., plus figures.
    • Wagner, W. H. and F. S. Wagner. 1993. Ophioglossaceae. In: Flora of North America Editorial Committee, eds. 1993. Flora of North America North of Mexico. 3+ vols. New York and Oxford. Vol. 2, pp. 85-106.
    • Wagner, W.H., and F.S Wagner. 1981. New Species of Moonworts, Botrychium Subgenus. Botrychium, From American Fern Journal 71:20-30.
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Citation for data on this website:
Mountain Moonwort — Botrychium montanum.  Montana Field Guide.  .  Retrieved on , from