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Montana Field Guide

Montana Field Guides

Dwarf woolly-heads - Psilocarphus brevissimus

Species of Concern
Native Species

Global Rank: G4
State Rank: S2S3
(see State Rank Reason below)
State Threat Score: No Known Threats
C-value: 8

Agency Status


External Links

State Rank Reason (see State Rank above)
Limited data combined with the posibility that several reported observations from western MT may be mis-identified with other Psilocarphus species make a precise determination of the species' status difficult.
  • Details on Status Ranking and Review
    Dwarf woolly-heads (Psilocarphus brevissimus) Conservation Status Review
    Review Date = 10/22/2012
    View State Conservation Rank Criteria
    Population Size

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

    Score1-2 - Low to Moderate. Occurs in 4-25 Subwatersheds (6th Code HUC’s), though the species' distribution is not sufficiently documented to place it within one class.

    CommentSeveral reported locations may be mis-identified and belong to either P. elatior or P. tenellus.

    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).


    Score0-3 - Population trends are unknown.

    CommentTrends are unknown.


    Score0-2 - Low to High Threat Levels.

    CommentUnclear if particular activities or dynamics such as grazing or weed invasion are negatively impacting populations or habitat.

    Intrinsic Vulnerability

    Score1-2 - Moderate to High Vulnerability.

    CommentSeed banking ability unknown? As an annual, may be more vulnerable to unfavorable conditions over consecutive years. However, seed banking and the species' ability to tolerate disturbance may limit it's vulnerability.

    Raw Conservation Status Score

    Score 6 to 13 total points scored out of a possible 19.

General Description
Dwarf Woolly-heads is a low annual with erect to prostrate, branched stems that are up to 5 cm tall. The alternate, lance-shaped leaves are 5-25 mm long, and the foliage is densely covered with white, tangled hairs. Minute flowers are borne in globose, woolly heads that are partially hidden among the upper leaves. Each flower and seed in the head is enclosed by a long-hairy bract that is ca. 3 mm long. A pappus is lacking.

Mature fruit June-early August.

Diagnostic Characteristics
Gnaphalium paulstre, a woolly annual of vernally moist habitats, and Filago arvensis, an introduced annual, may appear to be similar, but each has a pappus on top.

Species Range
Montana Range Range Descriptions


Range Comments
Eastern Washington to Baja California east to western Montana, eastern Wyoming and northern Utah, with disjunct populations in Chile and Argentina.

Observations in Montana Natural Heritage Program Database
Number of Observations: 25

(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)

Drying mud of ponds and other vernally wet soil in the valleys and on the plains.
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).

  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Cronquist, A. 1950. A review of the genus Psilocarphus. Research Studies of the State College of Washington 28(2):71-89.
    • 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.
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Citation for data on this website:
Dwarf woolly-heads — Psilocarphus brevissimus.  Montana Field Guide.  .  Retrieved on , from