Limestone Larkspur - Delphinium bicolor ssp. calcicola
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A Montana endemic.
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Limestone Larkspur (Delphinium bicolor ssp. calcicola) Conservation Status Review
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Limestone Larkspur is a perennial 10-30 cm tall arising from deep roots branched at least 1 cm below the stem attachment. Leaves are on the lower 1/3 of the stem, with 2-7 basal leaves at the time of flowering. Leaf blades are 1.5-7 cm long, round in outline, with few-many lobes, and glabrous to puberulent. Sepals are bright, dark blue, 16-21 mm long, and there is a cleft in the lower petals at least 2 mm deep.
Flowering late spring to early summer although usually somewhat later than the typical subspecies where the two overlap.
Distinguished from the widespread Delphinium bicolor ssp. bicolor by the bright blue sepals, the deep cleft in the lower petal blades 2 mm or greater, and upper petals with solid white-lavender tips rather than with distinct purple veins. Previous collections of this taxon have typically been identified as D. andersonii or D. geyeri.
Endemic to Montana.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Shortgrass prairie and grass-sagebrush communities on limestone-derived soils, usually with coarse fragments at the surface, or on limestone outcrops. 1300-2100 m elevation.
- Additional ReferencesLegend: View Online Publication
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- Heidel, B.L. 1995. Sensitive plant survey at the southern end of the Elkhorn Mountains, Broadwater and Jefferson Counties, Montana. Unpublished report to the Bureau of Land Management. Montana Natural Heritage Program, Helena, Montana. 12 pp. plus appendices.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Mincemoyer, S. 2005. Surveys of significant plant resources and related vegetation types for the Butte Office of the Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 11 pp + appendices.
- Poole, J.M. and B.L. Heidel. 1993. Sensitive plant surveys in the Big Belt and Elkhorn Mountains, Helena National Forest, Montana. Unpublished report to the Helena National Forest. Montana Natural Heritage Program. Helena, MT. 129 pp. plus printouts, maps.
- Sawyer, P.T. 1967. Taxonomic study of Montana DelphiniumS. Proceedings Montana Acadamy of Science 27:20-25.
- Vanderhorst, J.P. and B.L. Heidel. 1995. Sensitive plant survey in the Tobacco Root Mountains, Madison County, Montana. Unpublished report to the Beaverhead and Deerlodge National Forests. Montana Natural Heritage Program. Helena, MT. 66 pp. plus appendices.
- Vanderhorst, J.P. and P. Lesica. 1994. Sensitive plant survey in the Tendoy Mountains, Beaverhead County, Montana. Unpublished report to the Bureau of Land Management, Butte District. Montana Natural Heritage Program, Helena, MT. 59 pp. plus appendices.
- Warnock, M.J. 1995. A taxonomic conspectus of North American Delphinium. Phytologia 78(2):73-101.