Description from Flora of China
Herbs annual or biennial, (6-)15-55(-70) cm tall, pubescent with curved, usually subappressed trichomes. Stems erect, branched above. Basal leaves with petioles 0.5-3.5 cm; leaf blade obovate, spatulate, or oblanceolate, (1-)2.5-10(-15) × 0.5-3(-5) cm, margin pinnatifid or lyrate; lobes oblong, serrate or dentate, apex acute. Cauline leaves shortly petiolate; leaf blade oblanceolate or linear, 1-6 cm × (2-)5-10 mm, base attenuate to subcuneate, margin serrate or entire, apex acute. Infructescence lax or rarely dense; puberulent with curved, subappressed trichomes. Fruiting pedicels slender, straight, spreading, 2.5-4(-6) mm, usually glabrous abaxially. Sepals oblong, (0.5-)0.7-1(-1.1) × 0.5-0.7 mm, margin and apex white, pilose outside. Petals white, spatulate, 1-1.5(-2) × 0.2-0.6 mm, base attenuate, apex rounded, rarely rudimentary. Stamens 2; filaments 0.6-0.8 mm; anthers 0.1-0.2 mm. Fruit orbicular, 2.5-3.5(-4) mm in diam., narrowly winged apically, apex emarginate; apical notch 0.2-0.5 mm; style 0.1-0.2 mm, included in apical notch. Seeds reddish brown, ovate-oblong, usually narrowly winged at least distally, 1.3-1.7(-1.9) × 0.7-1 mm; cotyledons accumbent. Fl. Apr-Jun, fr. May-Sep. 2n = 32*.
The seeds are used medicinally.
Fields, roadsides, waste places, grassy areas; near sea level to 1000 m. Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Liaoning, Shandong, Sichuan, Taiwan, Yunnan, Zhejiang [Bhutan, India, Japan, Pakistan, Russia; native to North America; introduced elsewhere].