Anderson's Larkspur - Delphinium andersonii
This larkspur is a perennial with 1 to several erect, sometimes hollow stems, 15-50 cm tall, from a thick, branching root. The leaves are mostly confined to the lower 1/3 of the stem, the lowest ones withering by flowering time; the leaf blades are usually somewhat fleshy, 2-5 cm broad, and three times dissected into linear or oblong segments; the petioles of the lower leaves are 1-5 times as long as the blades; foliage is glabrous. The open inflorescence has one main stem with 3-15 flowers and usually 1 to several smaller side branches; the spreading sepals are 11-15 mm long and generally deep blue; the uppermost sepal has a long tubular portion (spur) projecting backwards; the lower petals are also deep blue and have a deep notch, 1/4-1/2 the length of the blade; the erect upper petals are whitish with blue tips; the stalk of each flower is 2-4 times the length of the calyx spur. The three-parted seed capsule is usually glabrous.
Delphinium is a difficult genus and a technical key should be consulted. Roots are necessary for positive identification.
Lesica (2012) believes reports of this species for Montana are based on misidenfications. It has been recorded for Ravalli County but that report should be rechecked (erbarium specimen data provided by University of Washington; accessed through the Consortium of Pacific Northwest Herbaria website, www.pnwherbaria.org, 2010-10-03).
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)
Sagebrush valleys and hills, into open forests; sparsely vegetated, sandy, probably calcareous soils.
- Additional ReferencesLegend: View Online Publication
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- Ewan, J. 1945. A synopsis of the North American species of Delphinium. University of Colorado Studies 2(2):55-242.
- Lesica, P. and P.L. Achuff. 1992. Distribution of vascular plant species of special concern and limited distribution in the Pryor Mountain desert, Carbon County, Montana. Unpublished report to the Bureau of Land Management. Montana Natural Heritage Program, Helena, MT. 105 pp.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.