Fl. Rocky Mts., 364, 1062. 1917.
Annuals; not scapose; (often glaucous), glabrous throughout. Stems erect, usually branched distally, rarely unbranched. Leaves basal and cauline; petiolate or sessile; basal not rosulate, petiolate, blade similar to cauline; cauline petiolate or sessile, blade (base not auriculate), margins entire, dentate, sinuate, or pinnatifid. Racemes (corymbose, several-flowered, lax), considerably elongated in fruit. Fruiting pedicels usually reflexed, rarely divaricate, slender or stout. Flowers: sepals erect, oblong, (unequal), lateral pair subsaccate basally; petals white or yellow (often veins purplish), spatulate, (slightly exceeding sepals, margins crisp), claw well-differentiated from blade, (apex obtuse); stamens in 3 unequal pairs; filaments not dilated basally; anthers ovate to oblong, (apiculate); nectar glands lateral, semi-annular, subtending lateral stamens, median glands absent. Fruits sessile, linear, smooth, latiseptate; valves each with prominent midvein; replum rounded or slightly flattened; septum complete; ovules (12–)16–28(–34); style distinct, (well-developed, adnate with valves and replum apex); stigma subentire. Seeds uniseriate, flattened, winged, oblong; seed coat not mucilaginous when wetted; cotyledons incumbent. x = 7.
w United States, nw Mexico.