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Montana Field Guide

Montana Field Guides

Spiny Greasebush - Glossopetalon spinescens
Other Names:  Glossopetalon nevadense

Species of Concern
Native Species

Global Rank: G5
State Rank: S1
(see State Rank Reason below)
State Threat Score: Unknown

Agency Status
USFS: Sensitive - Known in Forests (BRT)


External Links

State Rank Reason (see State Rank above)
A peripheral species in Montana where it is only known from one small occurrence on the Bitterroot National Forest. Population is vulnerable to human impacts as it occurs adjacent to a road.
  • Details on Status Ranking and Review
    Spiny Greasebush (Glossopetalon spinescens) Conservation Status Review
    Review Date = 05/06/2013
    View State Conservation Rank Criteria
    Population Size

    Score3 - Vey Small: Generally <2,000 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 - 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).


    ScoreNA - Rank factor not assessed.


    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.

    Intrinsic Vulnerability

    Score1 - Moderate Vulnerability: Specific biological attributes, unusual life history characteristics or limited reproductive potential makes the species susceptible to extirpation from stochastic events or other adverse impacts to its habitat and slow to recover.

    Raw Conservation Status Score

    Score 14 total points scored out of a possible 16 (Rarity factors and threats only).

General Description
Intricately branched, glabrous shrubs. Stems to 2 m high, thorny, ribbed, bearing old petiolar bases, green becoming tan. Leaves alternate, short-petiolate, narrowly oblanceolate, entire, 3–10 mm long; stipules lobed, adnate to the petiole. Flowers solitary at nodes of leaf-like bracts, perfect, perigynous; sepals 5, ovate, 1–2 mm long; petals 5, linear, ca. 3 mm long; stamens 6 to 10; pistil 1; ovary superior. Fruit an asymmetrical-ovoid, ribbed, leathery follicle 3–6 with 1 seed (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Montana plants are variety aridum M.E. Jones

Flowering in May or June.

Species Range
Montana Range Range Descriptions


Range Comments
OR (Harney and Wallowa cos), WA, ID, TX (Trans-Pecos), CA (south Klamath Ranges, Piute Mtns, Kern County, south High Sierra Nevada, north base of San Bernardino Mts., White and Inyo Mts, Desert Mtns), and northern MX.

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)

Rocky canyon walls in the lower montane zone.
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

Threats or Limiting Factors
Reported threats to Montana's population of Spiny Greasebush include disturbance from recreational use and competition with Spotted Knapweed (Centaurea stoebe). The state population is found at a popular climbing site, where it grows in the cracks of a large cliff. Evidence of shelter building using sticks and non-native plant material suggests substantial risk from overlapping stressors concentrated at the Spiny Greasebush population. Additional information is needed to understand the severity of impacts due to reported threats (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:
Spiny Greasebush — Glossopetalon spinescens.  Montana Field Guide.  .  Retrieved on , from