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Montana Field Guide

Montana Field Guides

Linearleaf Moonwort - Botrychium lineare
Other Names:  Slender Moonwort

Species of Concern
Native Species

Global Rank: G3
State Rank: S1S2
(see State Rank Reason below)
CCVI: Less Vulnerable

Agency Status
USFS: Sensitive - Known in Forests (KOOT)


External Links

State Rank Reason (see State Rank above)
This moonwort species is known to occur in western Montana from 6 locations, 5 of which are on federally-managed lands and the remaining site is located in a tribal wilderness area. However, occurrences are generally small in size and occupy roadsides or other similarly open or disturbed habitats. As such, it is vulnerable to activities such as weed invasion, weed spraying and road maintenance.
General Description
Linearleaf Moonwort is a small, perennial fern with a single pale green, above-ground frond which stands 6-18 cm tall. The frond is divided into two segments, one sterile, one fertile, which share a common stalk. The sterile segment is once-pinnate (with segments, or pinnae borne on each side of a elongated central axis) with 4-6 widely spaced pairs of pinnae which are linear shaped or sometimes bifid with linear lobes. The fertile segment is 1-2 times as long as the sterile segment and has a single major axis with short branches which bear grape-like sporangia which contain thousands of spores. Spores germinate underground and develop into minute, subterranean, non-photosynthetic gametophytes.

Frond probably maturing in August.

Diagnostic Characteristics
In Botrychium campestre the leaf rachis is broader and fleshy with the leaf segments closer together and sometimes overlapping. The individual segments are relatively shorter and broader with more divisions or lobes at the ends than in B. lineare. B. campestre also has a denser fleshy spore mass. Botrychium ascendens can also be quite similar, but the individual leaf segments are more strongly upright (ascending) and are generally more wedge-shaped, with the broader ends being more finely lobed or toothed. Unlike B. lineare, B. ascendens frequently bears some sporangia on the lower leaf segments.

Species Range
Montana Range Range Descriptions


Range Comments
In MT known from Lincoln, Lake and Glacier counties; in North America with widely separated populations in AK, WA, OR, ID, MT, CA-NV, and NB and QC (Donald Farrar, Iowa State University, unpublished).

Observations in Montana Natural Heritage Program Database
Number of Observations: 18

(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)

Botrychium lineare is an early- to mid-succession species that has been found throughout its range in a wide variety of habitats. These include mid-height grasslands, grazed rangelands, a limestone shelf on a steep slope, a woodland trail, roadside gravels and in grass under conifers. Montana populations, with the exception of the historic Mission Mountain site in Lake County, which was found along a steep woodland trail, were all found along roadways in gravelly shoulders created during road construction. Most of the associated vegetation is low, allowing ample direct sunlight for much of the day.

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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    • Barton, D. and S. Crispin. 2004. Conservation status of Botrychium lineare (slender moonwort) in Montana. Report to the U.S. Fish and Wildlife Service. Montana Natural Heritage Program, Helena, MT. 16 pp. plus appendices.
    • Farrar, Donald. 2011. Moonwort (Botrychium) Systematics. Ada Hayden Herbarium. Iowa State University.
    • Fish and Wildlife Service. Endangered and threatened wildlife and plants; 90-day finding for a petition to add Botrychium lineare (slender moonwort) to the list of threatened and endangered species. 50 CFR Part 17. Federal Register 65(91):30048-30049.
    • 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.
    • Wagner, W. H., Jr., and F. S. Wagner. 1994. Another widely disjunct, rare and local North American moonwort (Ophioglossaceae: Botrychium subg. Botrychium). American Fern Journal 84: 5-10.
    • Williston, P. 2003. Linear leaf Moonwort: a New Fern for Alberta. Iris: winter 2003. Page 12.
  • Web Search Engines for Articles on "Linearleaf Moonwort"
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Citation for data on this website:
Linearleaf Moonwort — Botrychium lineare.  Montana Field Guide.  .  Retrieved on , from