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Columbia Onion - Allium columbianum
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 Part of this occurrence has been replaced by a gravelpit.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
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
Range Comments
Regional endemic from eastern WA, northern ID and west-central MT.
Observations in Montana Natural Heritage Program Database
Number of Observations: 12
(Click on the following maps and charts to see full sized version)
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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
- Additional ReferencesLegend:
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Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
Rieseberg, L.H., P.M. Peterson, D.E. Soltis, and C.R. Annable. 1987. Genetic divergence and isozyme number variation among four varieties of Allium douglasii (Alliaceae). American Journal of Botany 74:1614-1624.
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