13. Clematis columbiana (Nuttall) Torrey & A. Gray, Fl. N. Amer. 1: 11. 1838.
Atragene columbiana Nuttall, J. Acad. Nat. Sci. Philadelphia 7: 7. 1834
Stems viny, climbing or trailing (mainly rhizomatous, not viny in var. tenuiloba ). Leaf blade consistently 2-3-ternate; leaflets diverse in shape, thin or ± succulent, usually deeply lobed, margins serrate. Flowers: sepals violet-blue (rarely white in var. columbiana ), lance-ovate to ovate.
Varieties 2 (2 in the flora): North America.
The name Clematis columbiana was formerly misapplied to C. occidentalis var. grosseserrata ; it is still associated with that taxon in some horticultural and popular publications. In such works, true C . columbiana is usually called C. pseudoalpina .
The two varieties of Clematis columbiana , although strikingly dissimilar in their extremes, intergrade extensively. The phenotype of C . columbiana var. tenuiloba may be at least in part a response to habitat; in some areas it grows on exposed summits while var. columbiana occurs nearby at lower elevations. In other areas, however, such as the Killdeer Mountains of North Dakota and the Black Hills of South Dakota and Wyoming, only the tenuiloba extreme is present.
The Thompson Indians used plants of Clematis columbiana medicinally in a head wash for scabs and eczema (D. E. Moerman 1986; varieties were not specified).