Herbs, annual, prostrate, glabrous, pubescent, or hispid. Branches 20-60 cm. Leaves opposite, even-pinnate, 1.5-5 cm, with 6-16 leaflets; leaflet blades oblong to obliquely oblong, 5-10 × 2-5 mm, base slightly oblique, margin entire, apex acute to obtuse. Flower ca. 1 cm in diam. Pedicel shorter than leaves. Sepals persistent. Stamens inserted on base of disk, with scale-form appendages. Ovary 5-angled, 5-locular, with 3 or 4 ovules per locule; stigma 5-parted. Schizocarp 4-6 mm, hard, pubescent or glabrous, with 5 carpels with 2 hardened 4-6 mm spines at mid margin, surface spiny or prickly. Fl. May-Aug, fr. Jun-Sep. 2n = 24, 30, 36, 48.

Sandy areas, wastelands, hillsides, residential areas; below 3300 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Hainan, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [almost worldwide].