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Montana Field Guide

Montana Field Guides

Annual Muhly - Muhlenbergia minutissima

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Species of Concern
Native Species

Global Rank: G5
State Rank: S3
(see State Rank Reason below)
State Threat Score: No Known Threats
C-value: 2

Agency Status


External Links

State Rank Reason (see State Rank above)
Muhlenbergia minutissima is known from 7 locations observed from 1895 to 2015 in central and western Montana. It is also reported to occur in northeast Montana, but specimens have not been located (Peterson in FNA 2003). A 1941 occurrence near Belgrade has been searched for in recent decades, but not re-located (Matt Lavin personal communication). Plants can occupy disturbed areas, yet populations may not be persisting. Surveys that bring forth current data on locations, populations sizes, habitat requirements, or threats is needed.
  • Details on Status Ranking and Review
    Annual Muhly (Muhlenbergia minutissima) Conservation Status Review
    Review Date = 10/29/2019
    View State Conservation Rank Criteria
    Range Extent

    ScoreE - 5,000-20,000 sq km (~2,000-8,000 sq mi)

    Comment14,797 square kilometers

    Area of Occupancy

    ScoreD - 6-25 4-km2 grid cells

    CommentPlant occurs in 7 of the 30,590 4x4 square-kilometer grid cells that cover Montana.

    Number of Populations

    ScoreB - 6 - 20

    Comment7 occurrences

    Environmental Specificity

    ScoreC - Moderate. Generalist or community with some key requirements scarce


    ScoreD - Low

General Description
Annual bunchgrass. Stems 5–39 cm. Leaves: blades 1–2 mm wide; ligule about 1 mm long. Inflorescence an open panicle 5–15 cm long. Spikelets 1–1.5 mm long. Lemmas unawned to awn-tipped, callus hairs few to absent (Lavin in Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Collected July and August.

Diagnostic Characteristics
This is our only annual Muhlenbergia with an open, spreading inflorescence. It could be confused with species of Panicum and Agrostis. A technical key and a hand lens or microscope are needed for positive determination.

Species Range
Montana Range Range Descriptions


Range Comments
Collected in Gallatin County; sporadic throughout western U.S. (Lavin in Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 9

(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)

Moist soil along rivers and streams in the valleys.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see

Threats or Limiting Factors
Threat impact not assigned because threats are not known (MTNHP Threat Assessment 2021).

  • Literature Cited AboveLegend:   View Online Publication
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • 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.
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Citation for data on this website:
Annual Muhly — Muhlenbergia minutissima.  Montana Field Guide.  .  Retrieved on , from