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Montana Field Guide

Montana Field Guides

Scallop-leaf Lousewort - Pedicularis crenulata

Species of Concern
Native Species

Global Rank: G4
State Rank: S1
(see State Rank Reason below)
State Threat Score: High
CCVI: Extremely Vulnerable
C-value: 6

Agency Status


External Links

State Rank Reason (see State Rank above)
Two known populations in Montana. Much of the riparian meadow habitat occupied by this species has been converted to agriculture or is being used as hay meadows.
  • Details on Status Ranking and Review
    Scallop-leaf Lousewort (Pedicularis crenulata) Conservation Status Review
    Review Date = 06/07/2012
    View State Conservation Rank Criteria
    Population Size

    Score2 - Small: Generally 2,000-10,000 individuals.

    Range Extent

    Score3 - Local Endemic or Very Small Montana Range: Generally restricted to an area <10,000 sq. miles (equivalent to the combined area of Phillips and Valley Counties) or <6 Sub-basins (4th code watersheds) Range-wide OR limited to one Sub-basin in Montana

    Area of Occupancy

    Score3 - Very Low: Generally occurring in 3 or fewer Subwatersheds (6th Code HUC’s).

    Environmental Specificity

    Score1-2 - Moderate to High.


    Score1-3 - Declining: Species is likely declining though the magnitude of declines is uncertain. Declines may be based upon range extent and/or occupied area in the recent past (approximately 30 years).

    CommentPopulation levels and extent have likely declined though the magnitude of the decline is uncertain.


    Score3 - Very High: >70% of the populations are being negatively impacted or are likely to be negatively impacted in the near future by one or more activities or agents that are expected to result in decreased populations and/or decreasing habitat quality and/or quantity.

    CommentInvasive weeds, hydrologic alterations, development and agricultural conversion are the primary threats.

    Intrinsic Vulnerability

    Score1-2 - Moderate to High Vulnerability.

    Raw Conservation Status Score

    Score 14 to 18 total points scored out of a possible 19.

General Description
Stems 15–40 cm, tomentose in lines, often clustered on the caudex. Leaves basal and cauline, sessile, 3–12 cm long; blades narrowly lanceolate, crenate. Inflorescence densely flowered, 2–10 cm long; leafy-bracteate. Flowers: calyx 8–12 mm long, villous; sepals 1–2 mm long fused into 2 lobes; corolla red to burgundy, 20–26 mm long; galea 9–15 mm long with an inconspicuous beak; lower lip inconspicuously lobed. Capsule 1–2 cm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range
Montana Range Range Descriptions


Range Comments
MT, WY south to CA, NV, UT and CO. Known from Beaverhead Co (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 4

(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)

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

The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans, Bombus appositus, Bombus bifarius, Bombus fervidus, Bombus flavifrons, Bombus frigidus, Bombus melanopygus, Bombus mixtus, Bombus rufocinctus, Bombus sylvicola, Bombus occidentalis, and Bombus kirbiellus (Plath 1934, Macior 1974, Wilson et al. 2010, Miller-Struttmann and Galen 2014, Williams et al. 2014).

Threats or Limiting Factors
Montana's populations of Scallop-leaf Lousewort are only known to occur in native riparian meadows along the upper Beaverhead River. Reported threats refer to extremely limited habitat, and the potential for future losses to agricultural development (MTNHP Threat Assessment 2021). A large proportion of potential habitat has been converted to hay production, and some has recently been displaced by an impoundment. A portion of an extant population occurs on private land and is at risk of similar losses to land conversion or consequences of surface water manipulation.

  • 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.
    • Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.
    • Miller-Struttmann, N.E. and C. Galen. 2014. High-altitude multi-taskers: bumble bee food plant use broadens along an altitudinal productivity gradient. Oecologia 176:1033-1045.
    • Plath, O.E. 1934. Bumblebees and their ways. New York, NY: Macmillan Company. 201 p.
    • Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ: Princeton University Press. 208 p.
    • Wilson, J.S., L.E. Wilson, L.D. Loftis, and T. Griswold. 2010. The montane bee fauna of north central Washington, USA, with floral associations. Western North American Naturalist 70(2): 198-207.
  • 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:
Scallop-leaf Lousewort — Pedicularis crenulata.  Montana Field Guide.  .  Retrieved on , from