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Montana Field Guide

Montana Field Guides

Pale Moonwort - Botrychium pallidum

Species of Concern
Native Species

Global Rank: G3
State Rank: S1S2
(see State Rank Reason below)

Agency Status


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State Rank Reason (see State Rank above)
Reported from a very small number of sites in Montana. All occurrences are small with the largest population count at a single site being approximately 30 plants. All known sites are in northwest Montana.
General Description
Pale Moonwort is a perennial with a single aboveground frond less than 10 cm tall, with a pale whitish green color, and divided into two segments that share a common stalk. The sterile segment is once pinnatifid and has up to 5 pairs of fanshaped pinnae, 2-3 mm long, with concave sides. The sterile segment is shaped like a trough along the central axis. The fertile segment is longer than the sterile segment, branched, and bears grape-like sporangia. Spores germinate underground and develop into subterranean gametophytes.

Fronds mature in June.

Diagnostic Characteristics
Resembles a very pale, dwarf form of B. minganense from which it is most readily distinguished by its very pale color, small pinnae less than 4 mm long, concave pinnae sides, and the trough-shape of the sterile segment rather than a flat blade.

Species Range
Montana Range


Range Comments
In MT known only from Lincoln and Flathead counties; according to Farrar (Iowa State University, unpublished ms.) the species ranges from eastern BC to QC and ME, south to CO, SD, MN, WI, MI, NY, VT and NH.

Observations in Montana Natural Heritage Program Database
Number of Observations: 16

(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)

Typically occurs in fescue grasslands in the valley zone, though may also be found in other open, mesic habitats. Common moonwort associates include B. hesperium, B. paradoxum, B. simplex and B. gallicomontanum. Other moonworts reported at B. pallidum sites include B. minganense, B. adnatum, B. pedunculosum, B. ascendens, B. lanceolatum, B. lunaria, B. crenulatum and B. michiganense.
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
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    • 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., P. Husby, and S. V. Cooper. 1998. Noteworthy collections: Montana. Madrono 45:328-330.
    • 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., Jr. and F. S. Wagner. 1990. Notes on the fan-leaflet group of moonworts in North America with descriptions of two new members. American Fern Journal 80:73-81.
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Citation for data on this website:
Pale Moonwort — Botrychium pallidum.  Montana Field Guide.  .  Retrieved on , from