Annuals, biennials, or perennials; caudex (or base) simple or branched (poorly developed); rarely scapose. Stems branched distally, (0.3–)0.5–3(–4.2) dm, pubescent proximally, often glabrous distally, trichomes simple, 0.1–1 mm, sometimes with fewer, stalked, 2-rayed ones. Basal leaves rosulate; shortly petiolate; petiole (0–0.5 cm), ciliate throughout; blade obovate to oblanceolate or linear-lanceolate, (0.3–)1–2.8(–3.5) cm × (1–)2–6(–9) mm, margins entire or denticulate, (ciliate, trichomes simple, 0.4–1 mm), surfaces usually pubescent, abaxially with stalked, 2–4-rayed trichomes, 0.05–0.4(–0.5) mm, (rarely with simple trichomes along midvein), adaxially with simple trichomes sometimes also with 2-rayed ones, 0.07–0.4 mm, rarely glabrous. Cauline leaves (0 or) 1–3(–5); sessile; blade lanceolate to elliptic or ovate, margins entire or denticulate, surfaces pubescent as basal. Racemes (2–)6–30(–50)-flowered, ebracteate, elongated in fruit; rachis straight or, rarely, flexuous, glabrous. Fruiting pedicels divaricate-ascending or horizontal, (not appressed to rachis), usually straight, rarely curved upward, (3–)5–14(–16) mm (subequaling or shorter than fruit), usually glabrous, rarely sparsely puberulent. Flowers (chasmogamous, petaliferous); sepals ovate, 1.4–2.1 mm, glabrous or sparsely pubescent, (trichomes simple); petals yellow, spatulate to oblanceolate, 2–3.2 × 0.7–1.2 mm; anthers ovate, 0.15–0.25 mm. Fruits lanceolate to narrowly elliptic or linear, plane, flattened, (4–)6–12(–15) × (1–)1.4–2.1 mm; valves glabrous; ovules (20–)24–38(–44) per ovary; style 0.01–0.12 mm. Seeds oblong, 0.7–1 × 0.4–0.5 mm. 2n = 24.
