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Montana Field Guide

Montana Field Guides

Columbia Onion - Allium columbianum

Species of Concern

Global Rank: G3
State Rank: S1
* (see State Rank Reason below)

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

External Links






State Rank Reason (see State Rank above)
Known from one occurrence in Camas Prairie. Part of this occurrence has been replaced by a gravelpit. Nearly all suitable habitat in the area has been converted to agriculture. Invasive weeds may also negatively impact the remaining habitat and threaten the population. Survey and monitoring data are needed.
  • Details on Status Ranking and Review
    Columbia Onion (Allium columbianum) Conservation Status Review
    Review Date = 11/07/2012
    View State Conservation Rank Criteria
    Population Size

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

    CommentPopulation size is apparently very small, though exact numbers are uncertain.

    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

    Score1-2 - Moderate to High.

    Trends

    Score2-3 - Moderate to Severe Declines:

    CommentDeclines have taken place as part of one population was impacted by a gravelpit, though the severity of the decline is uncertain.

    Threats

    Score2-3 - High to Very High.

    CommentDevelopment (gravelpit) and invasive species are the primary threats to the species.

    Intrinsic Vulnerability

    Score0-1 - Low to Moderate Vulnerability.

    Raw Conservation Status Score

    Score 14 to 18 total points scored out of a possible 19.

 
General Description
Bulbs globose, solitary or clustered; outer coat membranous, lacking reticulations. Scapes terete, 20–40 cm. Leaves 2, falcate, flat, 3–12 mm wide, persistent. Umbel hemispheric to globose with 20 to 50 flowers; pedicels 6–10 mm long; bracts 3, ovate, apiculate. Flowers rose to magenta; tepals 6–9 mm long; ovary with 6 low, rounded crests; stamens ca. as long as the tepals. Seed surface smooth (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Phenology
Flowering in June.

Diagnostic Characteristics
The broad sickle-shaped leaves and swollen stem beneath the inflorescence distinguish it from other species of Allium in our area.

Species Range
Present
 


Range Comments
Regional endemic from eastern WA, northern ID and west-central MT.

Summary of Observations Submitted for Montana
Number of Observations: 11

(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
Moist swales and along vernal ponds and streams in the valleys.

References
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Citation for data on this website:
Columbia Onion — Allium columbianum.  Montana Field Guide.  .  Retrieved on , from