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Montana Field Guide

Montana Field Guides

Dwarf Purple Monkeyflower - Mimulus nanus

Species of Concern

Global Rank: G5
State Rank: S2S3
* (see State Rank Reason below)

Agency Status
USFWS:
USFS: SENSITIVE
BLM:
MNPS Threat Rank: 2
C-value: 6

External Links






State Rank Reason (see State Rank above)
Mimulus nanus is only known from a few extent occurrences in the state, plus two historical collections. Populations are generally small and in habitats susceptible to weed invasion. At least a few of the occurrences contain scattered spotted knapweed plants.
  • Details on Status Ranking and Review
    Dwarf Purple Monkeyflower (Mimulus nanus) Conservation Status Review
    Review Date = 05/29/2013
    View State Conservation Rank Criteria
    Population Size

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

    CommentData supports an estimate of approximately 10,000 plants. However, population levels likely fluctuate widely.

    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

    Score2 - Low: Generally occurring in 4-10 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).

    Trends

    ScoreNA - Rank factor not assessed.

    CommentTrends are unknown, though there is no indication that the species' has experienced significant declines in Montana. Some habitat loss may have occurred.

    Threats

    Score1-2 - Medium to High.

    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 9 to 10 total points scored out of a possible 16 (Rarity factors and threats only).

 
General Description
Dwarf Purple Monkeyflower is a small annual with branched stems that are up to 10 cm high. The opposite, narrowly elliptic leaves are up to 35 mm long and have petioles on the lower stem but are sessile above. Foliage is glandular-hairy. The paired, sessile flowers are borne in the axils of upper leaves. The glandular, tubular calyx is 5-8 mm long and has 5 pointed lobes. The magenta, tubular corolla is 10-25 mm long and 2-lipped with 2 rounded upper and 3 lower lobes. There are yellow markings near the throat of the tube. Numerous seeds are contained in a round capsule.

Phenology
Flowering June-July.

Diagnostic Characteristics
Mimulus breweri is also an annual with purplish flowers, but its corollas are less than 10 mm long and it does not occur in dry habitats.

Species Range
Present
 


Range Comments
WA south to northern CA, east to southwestern MT, Yellowstone N.P., and northeastern NV.

Summary of Observations Submitted for Montana
Number of Observations: 29

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Dry, open, often gravelly or sandy slopes in the valleys and foothills.

References
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Citation for data on this website:
Dwarf Purple Monkeyflower — Mimulus nanus.  Montana Field Guide.  .  Retrieved on , from