Description

Key Characters:

Growth Form: Annual or biennial herbs, pubescent with simple hairs.

Stems: Stems prostrate to ascending, 1–2(–3) dm long, usually branched from near the base, sparsely short–hirsute (hairs slender) or glabrous.

Roots:

Leaves: Leaves simple. Alternate or rarely opposite. Basal leaves 1–5 cm long, 1–2 times pinnately dissected, the lobes 0.6–3 mm wide; cauline leaves few, pinnately lobed, the segments obtuse to subacute. Margins dissected and serrate. Petioles of basal leaves (0.5–)1–3 cm. Cauline leaves sessile, rarely shortly petiolate. Stipules absent.

Flowers: Flowers usually bractless in elongate racemes 2–10 cm long, only slightly narrowed toward apex. Flowers bisexual (perfect), actinomorphic or rarely slightly irregular; white, pale yellow, or greenish, usually 2–3 mm long, sometimes absent. Calyx of 4 sepals, deciduous, erect, usually oblong, sometimes the inner 2 with gibbous bases that hold the nectar; usually magenta, ca. 0.8 mm long, often persistent in fruit, margins white. Corolla of 4 petals, rarely absent, yellow, white, or lavender, entire to emarginate, rarely lobed or fimbriate, usually with an elongate claw; linear, less than 0.5 mm long, or absent. Stamens 2; anthers dithecal, opening by longitudinal slits. Ovary superior, 2(4?)-carpellate, usually 2-celled by means of a false, but usually complete septum, rarely 1-celled, sessile or rarely stipitate; ovules 1 to numerous, borne on parietal placentas on replum margin at periphery of ovary wall, campylotropous or occasionally anatropous; styles short or essentially absent; stigma capitate.

Fruit: Capsules divided into 2 cells by the usually thin and membranous septum; elongate (at least 3 times as long as wide) and referred to as a silique; flattened at right angles to the septum; broadly elliptic to obovate or suborbicular; 2.5–3.5 mm long; the apical notch broad; prominent; the margins clearly exceeding the style. Seeds 1 to numerous; ca. 1.5 mm long; often becoming mucilaginous when wet; endosperm essentially absent.

Ploidy:

Habitat: Naturalized in dry; disturbed sites.

Elevation Range: 0–200 m.