Annuals; puberulent or hirsute. Stems simple or several from base, erect to ascending or (outer ones) decumbent, unbranched or branched, 0.2-1.5(-3.8) dm. Basal leaves (soon withered); not rosulate; petiole often undifferentiated (to 3 cm); blade linear, 2-10 cm × 1-4 mm, margins entire, dentate, or pinnatisect (lobes 2-10 pairs, margins entire or dentate). Cauline leaves similar to basal, smaller, blade base attenuate, not auriculate, margins entire. Racemes (subcapitate to cylindrical), elongated or not in fruit, (compact); rachis puberulent, trichomes straight, cylindrical. Fruiting pedicels erect to slightly ascending, straight and appressed to rachis or distally slightly recurved, (strongly flattened), 2.5-5 × 0.9-1.4 mm, usually puberulent throughout, rarely only adaxially. Flowers: sepals (somewhat persistent), ovate, 1.1-1.4 × 0.6-0.8 mm; petals greenish, obovate-oblong, 1.9-3 × 0.8-1.3 mm, claw absent, (usually pubescent outside, with fringed margin, rarely glabrescent); stamens 4, median; filaments 0.8-1.1 mm; anthers 0.15-0.2 mm. Fruits oblong-ovate, 5-7 × 2.8-4 mm, apically winged, apical notch 1.4-2.8 mm deep; valves thick, smooth, strongly reticulate-veined, hirsute and puberulent, (trichomes spreading, mixed with smaller ones); style obsolete, included in apical notch. Seeds oblong, 2-2.4 × 1.1-1.3 mm. Flowering Mar-Jun. Margins of vernal pools, edges of salt marshes, alkaline flats and adobe, pastures, mud-wet fields; 0-700 m; Calif.; Mexico (Baja California). Variety heckardii, which is said to differ from var. latipes mainly by having elongated stems simple at base (instead of short and branched basally), grows mixed with var. latipes in single populations. It appears that the difference is trivial and may well be controlled by a few-gene difference. In our opinion, formal distinction is unwarranted; similar conditions exist in other species (e.g., 27. Lepidium nitidum).