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Montana Field Guide

Montana Field Guides

Stalk-leaved Monkeyflower - Mimulus ampliatus
Other Names:  Mimulus patulus, Mimulus washingtonensis

Species of Concern
Native Species

Global Rank: G3
State Rank: S3
(see State Rank Reason below)

Agency Status
MNPS Threat Rank:
C-value: 7

External Links

State Rank Reason (see State Rank above)
See rank details.
  • Details on Status Ranking and Review
    Stalk-leaved Monkeyflower (Mimulus ampliatus) Conservation Status Review
    Review Date = 04/01/2013
    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.

    CommentPopulation levels are poorly documented and likely fluctuate widely from year to year.

    Range Extent

    Score2 - Regional or State Endemic or Small Montana Range: Generally restricted to an area <100,000 sq. miles (equivalent to 2/3 the size of Montana or less) or Montana contributes 50% or more of the species’ range or populations OR limited to 2-3 Sub-basins in Montana.

    Area of Occupancy

    Score1 - Moderate: Generally occurring in 11-25 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.

    CommentTrends are unknown, though there is no indication that the species' has experienced severe declines in Montana.


    Score0-1 - Low to Medium.

    CommentSome occurrences are near areas of human-use and have the potential to be negatively impacted. However, no threats have been identified that would be high in terms of scope or severity.

    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 6 to 8 total points scored out of a possible 16 (Rarity factors and threats only).

General Description
Annual. Stems erect, simple or branched, 2–12 cm. Herbage glabrate to glandular-puberulent. Leaves petiolate; blade ovate, dentate, 2–10 mm long. Flowers: calyx purplish, 4–8 mm long, ca. 0.5 mm long; pedicel 2-3 times as long as calyx; corolla yellow, 10–15 mm long, bilabiate, lower lip longer, little deflexed from the upper lip. Capsule 3–6 mm long (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Flowering in late June - early July.

Diagnostic Characteristics
MT specimens have previously been incorrectly referred to M. patulus or M. washingtonensis. Additionally, most past reports of M. floribundus were mis-identified and belong here.

Species Range

Range Comments
Endemic to central ID and western MT (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 33

(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 seeps and vernally moist soil along slopes, cliffs and streams from the valleys to the subalpine zone.

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Citation for data on this website:
Stalk-leaved Monkeyflower — Mimulus ampliatus.  Montana Field Guide.  .  Retrieved on , from