Odontarrhena obovata C. A. Meyer in C. F. von Ledebour, Fl. Altaica 3: 61. 1831; Alyssum americanum Greene; A. biovulatum N. Busch; A. fallax Nyárády

Perennials; (cespitose, caudex often woody); canescent throughout, trichomes 10-25- rayed. Stems often several from base (often with sterile shoots), usually erect or ascending, 0.7-1.5(-2) dm. Cauline leaves subsessile; blade broadly oblanceolate, obovate-spatulate, or obovate, 0.6-1.4(-1.7) cm × (1-)2-6 mm (gradually smaller distally), base attenuate, apex rounded, obtuse, or subacute. ( Racemes corymbose, simple, or in panicles terminating each stem.) Fruiting pedicels divaricate, straight, slender, (2-)3-7(-9) mm, trichomes uniformly stellate. Flowers: sepals oblong, 1.5-2 × 0.7-1 mm, stellate-pubescent; petals yellow, broadly spatulate, 2.5-3.5(-4) × 1-1.5 mm, base attenuate, apex often obtuse or rounded, glabrous abaxially; filaments: median pairs unilaterally broadly winged, apically 1-toothed, lateral pair with lanceolate or narrowly oblong basal appendage, apically obtuse or subacute, 1.5-2 mm; anthers oblong, 0.3-0.4 mm. Fruits broadly elliptic or obovate, 3-4.5(-5) × 2.5-3.5 mm, apex obtuse to rounded; valves inflated at middle or on 1 side, flattened at margins, densely stellate-pubescent; ovules (1 or) 2 per ovary; style (slender), 1.5-2 mm, glabrous. Seeds ovoid, compressed, 1-1.7 × 0.8-1.2 mm, not winged or margined. 2n = 16, 32.

Flowering May-Jul. Mountain slopes, cliffs, gravel, rocky places; 500-1500 m; Yukon; Alaska; c, e Asia.