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Montana Field Guide

Montana Field Guides

Woolly Prince's plume - Stanleya tomentosa

Potential Species of Concern

Global Rank: G4
State Rank: S3S4
* (see State Rank Reason below)

Agency Status
MNPS Threat Rank:

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State Rank Reason (see State Rank above)
See rank details.
  • Details on Status Ranking and Review
    Woolly Prince's plume (Stanleya tomentosa) Conservation Status Review
    Review Date = 09/21/2012
    View State Conservation Rank Criteria
    Population Size

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

    CommentThough precise population numbers are lacking, it appears that population numbers are less than 10,000 plants.

    Range Extent

    Score2-3 - Local or Regional Endemic: Species has a small to very small range, though its distribution is either imprecisely documented or information to precisely categorize it was lacking at the time its status was reviewed.

    CommentEndemic to Carbon Co and adjacent WY with a possible population in ID.

    Area of Occupancy

    Score2 - Low: Generally occurring in 4-10 Subwatersheds (6th Code HUC’s).

    CommentLimited to a few subwatersheds in the Bighorn basin. Additional collection data may show it to occur in additional subwatersheds in the vicinity.

    Environmental Specificity

    Score1 - Moderate: Species is restricted to a specific habitat that is more widely distributed or to several restricted habitats and is typically dependent upon relatively unaltered, good-quality habitat (C Values of 5-7).


    Score0-1 - Stable to Minor Declines:

    CommentTrends are undocumented, but it does not appear that the species has experienced moderate or severe declines and habitat remains largely intact.


    Score0-1 - Low to Medium.

    CommentThreats to the species' viability are unknown, though initial assessments indicate that the the magnitude of any threats are probably low.

    Intrinsic Vulnerability

    Score0-1 - Low to Moderate Vulnerability.

    CommentSpecific life history attributes which may limit the species' viability are undocumented.

    Raw Conservation Status Score

    Score 7 to 11 total points scored out of a possible 19.

General Description
Perennial (monocarpic?) from a simple or few-branched caudex covered in old leaf bases. Stems erect, simple, 40–120 cm. Leaves basal and cauline; basal leaves petiolate, 10–30 cm long, oblanceolate, pinnately lobed, the terminal lobe largest; stem leaves similar below, becoming entire above. Vestiture of dense long, simple hairs at least below. Petals pale yellow, 10–15 mm long, glabrous. Fruit slightly curved, 3–8 cm long, constricted between the seeds; the stipe 15–25 mm long; pedicels spreading, 10–15 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Species Range

Range Comments
Regional endemic; in Wyoming known from the Big Horn Basin and the foothills of the Absaroka, Big Horn, Bridger, and Owl Creek mountains in Big Horn, Fremont, Hot Springs, and Park counties.

Summary of Observations Submitted for Montana
Number of Observations: 44

(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)

Open, gravelly soil of slopes and flats in sagebrush grassland, desert shrubland, and juniper woodland in the valley and foothill zones.

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Citation for data on this website:
Woolly Prince's plume — Stanleya tomentosa.  Montana Field Guide.  .  Retrieved on , from