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Montana Field Guides

Slender Wedgegrass - Sphenopholis intermedia
Other Names:  Sphenopholis obtusata var. major

Potential Species of Concern
Native Species

Global Rank: G5
State Rank: S3S4
(see State Rank Reason below)
State Threat Score: Unknown

Agency Status


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State Rank Reason (see State Rank above)
Rare in Montana, where it has only been documented from a very few collections, though the population data required to more precisely assign a conservation rank are lacking.
  • Details on Status Ranking and Review
    Slender Wedgegrass (Sphenopholis intermedia) Conservation Status Review
    Review Date = 02/22/2013
    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

    Score1 - Moderate: Generally occurring in 11-25 Subwatersheds (6th Code HUC’s).

    Environmental Specificity

    Score0-1 - Low to Moderate.

    CommentVarious mesic sites. May respond favorably to some disturbance.


    Score0-1 - Stable to Minor Declines:


    Score0-1 - Low to Medium.

    Intrinsic Vulnerability

    Score0 - Low Vulnerability: Species does not have any unusual or specific life history or biological attributes or limted reproductive potential which makes it susceptible to extirpation from stochastic events or other adverse impacts to its habitat and thus slow to recover.

    Raw Conservation Status Score

    Score 3 to 7 total points scored out of a possible 19.

General Description
Stems 30–100 cm. Leaves: blades flat, 2–6 mm wide. Inflorescence nodding open panicle, 7–20 cm long. Spikelets 2.5–4 mm long; second glume typically broadest below the tip. Lemmas 2–3 mm long (Lavin in Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Fruiting in July - August.

Diagnostic Characteristics
This species is distinguished from the more common Sphenopholis obtusata by the relatively open inflorescence in which branches are evident, pointed glume tips, and lemma length 2.5 mm or greater.

Range Comments
Sporadic throughout most of North America (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: 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)

Wet site inhabiting, often in disturbance-prone settings (Lavin in Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

  • 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?
    • Heidel, B.L. and K.H. Dueholm. 1995. Sensitive plant survey in the Sioux District, Custer National Forest, 1994, Carter County, Montana and Harding County, South Dakota. Unpublished report to the Custer National Forest. Montana Natural Heritage Program, Helena, Montana. 95 pp. plus appendices.
    • 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:
Slender Wedgegrass — Sphenopholis intermedia.  Montana Field Guide.  .  Retrieved on , from