Monographs Details: Draba oreibata var. serpentina Tiehm & P.K.Holmgren
Authority: Tiehm, Arnold & Holmgren, Patricia K. 1991. A New Variety of Draba oreibata (Brassicaceae) from Nevada, U.S.A. Brittonia. 43 (1): 20-23.
Family:Brassicaceae
Discussion:

A var. oreibata habitu robustiori, foliorum lamina abruptius dilatata, floribus majoribus, necnon patria remota alpina (ultra 3000 m alta) diversa.

TYPE: U.S.A. NEVADA. White Pine Co.: Snake Range, upper Snake Creek drainage, W side of Pyramid Peak, T13N R68E S36, frequent among quartzite boulders, usually in cracks of rocks, S exposure, 3475 m (11,400 ft), 28 Jun 1966, Noel H. Holmgren & James L. Reveal 2761 (HoLoTPE: NY!; ISOTYPES: GH

Additional specimens: U.S.A. Nevada. White Pine Co., Snake Range: on W slope of Pyramid Peak, on quartzite slope, 3620 m (11,880 ft), 10 Aug 1964, Noel H. Holmgren t James L. Reveal 1584 (oH, NY); W side of Pyramid Peak, above Johnson Lake, T13N R68E, 3475 m (11,400 ft), 15 Jul 1970, Noel H. Holmgren & Patricia K Holmgren 4427 (OH, NY); near Baker Lake, 22 Aug 1983, G. L Clifton 11759 (PUA); Great Basin Nat'l Park, area of Wheeler Peak, cirque above cabin near Baker Creek Trail, in rock crevices and on protected ledges, 13 Sep 1987, Robert A. Price 952 (NY). Lander Co.: Toiyabe Range, head of Carseley Creek, T15N R43E S17, 10,000 ft, 5 Aug 1978, S. Goodrich 12107 (BRY, GH)

Draba oreibata var. serpentina differs from var. oreibata in its more robust habit, in broader, more abruptly dilated leaf blades that tend to be more sharply acute at the apex, and in larger flowers. Variety serpentina is known only from over 3000 m elevation in the Snake and Toiyabe ranges of Nevada, at least 600 km from the known localities of var. oreibata in the Lost River and Lemhi ranges in Idaho. The differences between the two varieties, none of them individually diagnostic, are given in the key.

Another possible relative of variety serpentina is D. subalpina Goodman & C. L. Hitchc., which occurs in Garfield, Iron, Kane and Millard counties, Utah, from 2130 to 3295 m elevation. It is similar to D. oreibata in being a white-flowered scapose perennial. The trichomes of D. subalpina sometimes are all simple and arranged as cilia on the leaf margins but usually some or all are branched and occur on other parts of the leaves as well as on the lower part of the stem. Draba subalpina further differs in having shorter, broader siliques, more flowers per inflorescence, fewer rosettes per plant, leaves of thicker texture, and in its habitat being on limestone gravels