Annuals; not scapose; (usually glaucous), pubescent or glabrous, trichomes simple, 2-forked, dendritic. Stems erect, unbranched or branched distally. Leaves basal and cauline; petiolate; basal rosulate or not, blade margins pectinate or pinnatisect; cauline blade (base not auriculate), margins pectinate or pinnatisect, (terminal lobes filiform and semiterete, or linear and flat). Racemes (several-flowered), considerably elongated in fruit. Fruiting pedicels divaricate-ascending, divaricate, horizontal, or reflexed, slender [stout]. Flowers: sepals erect, oblong [ovate], lateral pair not saccate basally (usually glabrous, rarely pubescent); petals white, purple, or lavender, spatulate [oblanceolate] (longer than sepals), claw differentiated from blade, (often oblanceolate, equal to or longer than sepals, apex obtuse to emarginate); stamens slightly tetradynamous; filaments not dilated basally; anthers ovate or oblong; nectar glands lateral, semi-annular or annular, median glands absent. Fruits sessile or shortly stipitate, linear, smooth or torulose, latiseptate [terete]; valves each with prominent or obscure midvein, pubescent or glabrous; replum rounded; septum complete; ovules [14-]16-40[-94] per ovary; style distinct; stigma capitate, entire. Seeds uniseriate or biseriate, (yellowish brown), flattened or plump, not winged, oblong; seed coat not mucilaginous when wetted; cotyledons accumbent [incumbent]. x = 13, 14.
Resembling Cardamine and Arabis; sep erect; pet small, white to pink or purple; nectar-glands small, associated with individual stamens, or obsolete; anthers oblong; fr linear, flattened parallel to the septum or subterete, the valves nerveless or faintly 1-nerved at the base; replum narrow, not margined; seeds several and uniseriate in each locule, narrowly winged (in our sp.) or wingless; annual or biennial herbs, glabrous or sparsely pubescent below with simple or branched hairs; lvs pinnatifid. 10, N. Amer., mainly western.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.