[Illustration: Draba andina (Nutt.) A. Nelson. (⅔ Nat.) Mountain Whitlow-Grass.] [Sidenote: =Draba glacialis= Adams.] Caudex much branched, branches short and slender. Leaves strongly keeled, ¼—¾ of an inch long, more or less loosely stellate-pubescent, sometimes ciliate at the base. Scapes slender, ¼—6 inches high, hairy or nearly smooth; racemes few-flowered; sepals with a few long hairs or smooth petals ⅛ of an inch long, pale yellow, darker at the base; pod ¼ of an inch or more long, narrowly oblong, acute at both ends, on pedicels ¼ of an inch or more long; style distinct. In dry, exposed stony places throughout the Rockies, flowering in early spring. [Sidenote: =Draba oligosperma= Hook.] Stems much branched from the root, densely tufted at the base. Leaves erect, linear, obtuse, tapering to the base, stiff, ciliate, with stellate hairs on both sides, especially toward the apex. Scapes naked; flowers racemose; calyx smooth or with scattered hairs, petals white or pale yellow, obovate, ⅛ of an inch or more long, pods short, nearly orbicular, acute at the apex, more or less rounded at the base, sparingly short-hairy, ⅛ of an inch long; style ⅓ its length. Alpine summits and dry ridges throughout the Rockies; flowering in May and June. [Sidenote: =Draba andina= (Nutt.) A. Nelson.] Densely cæspitose. Leaves linear-oblong, obtuse, ⅛ of an inch long or less, stiff and rigid, densely imbricated, forming numerous small rosettes: stellate-pubescent on both sides. Scapes slender, 1—2 inches high, few-flowered, petals pale yellow or white, ⅛ of an inch long; twice as long as the hairy calyx; pods ⅛ of an inch or less long with short stiff hairs. On exposed rocks and alpine summits throughout the Rockies, frequent in the vicinity of Banff, flowering in May and June. [Sidenote: =Draba nivalis= Liljb. _Arctic Whitlow-grass._] Caudex with numerous slender matted branches. Leaves in dense tufts, oblanceolate, acutish with a rather stout mid-nerve, entire, white-hairy, with dense stellate pubescence, not at all ciliate or slightly so near the base, ¼ of an inch long or less. Scapes slender, hairy, 1—3 inches high, calyx hairy; flowers ⅛ of an inch high, the white petals slightly exceeding the calyx; pods few, usually smooth, oblong, acute at each end, ½ of an inch or less long on short pedicels and with a short stout style and 2-lobed stigma. On alpine summits and exposed ledges throughout the Rockies; flowering in June. [Illustration: Draba glacialis Adams. (⅔ Nat.) Whitlow-Grass.] [Illustration: Draba aurea Vahl. (½ Nat.) Golden Whitlow-Grass.] [Sidenote: =Draba lonchocarpa= Rydb.] Similar to the preceding species but with the leaves obtuse; pods ⅓—⅔ of an inch long, smooth, very narrow and usually more or less twisted, on slender pedicels ¼—½ an inch long. In moist or shaded ground, on alpine summits or on ledges, throughout the Rockies; flowering in June. [Sidenote: =Draba aurea= Vahl. _Golden Whitlow-grass._]