Description from Flora of China
Lepidium neglectum Thellung.
Herbs annual or biennial, (10-)25-50(-65) cm tall, puberulent with minute straight papillae, rarely glabrous. Stems erect, branched above. Basal leaves rosulate, withered early; petiole 0.5-1.5(-2) cm; leaf blade often oblanceolate, rarely spatulate or oblong, (1.5-)2.5-8(-11) cm × 5-10(-20) mm, base attenuate, margin coarsely serrate or pinnatifid, apex acute. Cauline leaves shortly petiolate; leaf blade narrowly oblanceolate or linear, irregularly serrulate or dentate, rarely subentire, reduced in size upward. Infructescences dense; rachis papillae straight, slender or subclavate. Fruiting pedicels slender, divaricate, slightly recurved, somewhat flattened, (1.5-)2-3.5(-4) mm, puberulent or papillate adaxially. Sepals oblong, 0.5-0.8(-1) × 0.3-0.5 mm, glabrous or sparsely pilose near apex, margin white. Petals usually absent, rarely filiform and 0.3-0.9 mm. Stamens 2; filaments filiform, 0.6-1 mm; anthers ovate, 0.1-0.2 mm. Fruit obovate to obovate-suborbicular, (2-)2.5-3(-3.5) × 1.5-2.5(-3) mm, widest above middle, apex obtuse or emarginate; apical wings ca. 0.5 mm; apical notch 0.2-0.4 mm; style 0.1-0.2 mm, included in apical notch. Seeds brown, ovate, wingless or obscurely winged, 1.1-1.3(-1.5) × 0.8-0.9 mm; cotyledons incumbent. Fl. May-Jun, fr. Jun-Jul. 2n = 32.
Seashores, sandy places, roadsides; near sea level to 3800 m. Hebei, Heilongjiang, Jilin, Liaoning, Shandong, Yunnan [Korea, Mongolia, Russia, Tajikistan; native to North America; introduced elsewhere].