Annuals or perennials; (short-lived); caudex branched (when present); usually scapose. Stems unbranched or, rarely, branched distally, (0.1-)0.3-1.1(-1.5) dm, usually glabrous throughout, rarely pubescent proximally, trichomes simple, 0.3-0.7 mm. Basal leaves rosulate; petiolate; petiole ciliate throughout; blade oblanceolate to obovate, (0.2-) 0.5-2.5(-3) cm × (1-)2-4(-6) mm, margins usually entire, rarely denticulate, (sometimes ciliate), surfaces glabrous or sparsely pubescent, with simple and 2-rayed trichomes, 0.3-0.9 mm. Cauline leaves usually 0, rarely 1; sessile; blade oblong to ovate, margins entire, surfaces glabrous. Racemes (2-)4-15(-25)-flowered, ebracteate, elongated in fruit; rachis slightly flexuous or straight, glabrous. Fruiting pedicels horizontal to divaricate-ascending, usually straight, rarely curved upward, 3-8 (-10) mm (subequaling or shorter than fruit), glabrous. Flowers (chasmogamous, petaliferous); sepals (green or purplish), ovate, 1-2 mm, glabrous; petals yellow (often fading white), oblanceolate, 1.5-2.5(-3) × 0.5-1 mm; anthers ovate, 0.15-0.25 mm. Fruits usually narrowly elliptic to lanceolate, rarely linear-lanceolate, plane, flattened, (3-)5-10 × 1.5-2.5 mm; valves glabrous; ovules (8-)16-24(-30) per ovary; style 0.02-0.1 mm. Seeds elliptic, 0.7-0.8 × 0.4-0.5 mm. 2n = 40.
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