Description

Key Characters:

Growth Form: Erect, unbranched to many-branched annual herbs, hirsute at least below.

Stems:

Roots:

Leaves: Leaves simple. Alternate or rarely opposite. Blades lyrate–pinnatifid to pinnately divided, 7–15 cm long, usually 3–7 cm wide, upper leaves smaller, lanceolate to hastate. Margins coarsely dentate. Petioles (1–)2–7(–10) cm long. Stipules absent.

Flowers: Flowers usually bractless, in dense racemes elongating in fruit. Flowers bisexual (perfect), actinomorphic or rarely slightly irregular. Calyx of 4 sepals, deciduous, erect, usually oblong, sometimes the inner 2 with gibbous bases that hold the nectar, ca. 3 mm long, sparsely hirsute. Corolla of 4 petals, pale yellow, ca. 3 mm long, entire to emarginate, rarely lobed or fimbriate, usually with an elongate claw. Stamens (2–4)6(–16), tetradynamous, the inner 4 usually in pairs, sometimes connate at base in pairs; 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; style 1 or occasionally absent; stigma capitate or rarely decurrent, entire or 2-lobed.

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; subulate; strictly erect and appressed to the stem; 1–2 cm long; hirsute or glabrous; dehiscent from the base upward; exposing the septum; sometimes fruit indehiscent or dehiscent and jointed between the seeds; ± breaking up at maturity. Seeds 1 to numerous; ca. 1 mm long; often becoming mucilaginous when wet; endosperm essentially absent.

Ploidy: 2n = 14

Habitat: Naturalized in cultivated land and pastures.

Elevation Range: