Description from Flora of China
Herbs annual. Stems erect, 40-90 cm tall, branched, glabrous, subglabrous, or lanose, swollen at nodes. Petiole 2-5 mm, appressed hispidulous; leaf blade with large blackish spot adaxially, lanceolate or broadly lanceolate, 5-15 × 1-3 cm, abaxially nearly glabrous or densely lanose, adaxially nearly glabrous, sometimes densely lanose on both surfaces, base cuneate, margin ciliate, apex acuminate or acute; ocrea brownish, tubular, 1.5-3 cm, membranous, glabrous, apex truncate, not ciliate or rarely shortly ciliate. Inflorescence terminal or axillary, spicate, erect or nodding, 3-8 cm, densely flowered, several spikes aggregated and panicle-like; peduncles glandular; bracts funnel-shaped, margin sparsely shortly ciliate. Perianth pink or white, 4(or 5)-parted; tepals 2.5-3 mm, veins strongly forked, curved downward near apex. Stamens usually 6. Styles 2, connate at base. Achenes included in persistent perianth, black-brown, shiny, broadly ovoid, biconcave, 2-3 mm. Fl. May-Jul, fr. Jun-Oct. 2n = 22.
Roadsides, along ditches, field margins, watersides; sea level to 3900 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [Bangladesh, Bhutan, India, Indonesia, Japan, Kazakhstan, Korea, Kyrgyzstan, Malaysia, Mongolia, Myanmar, Nepal, New Guinea, Pakistan, Philippines, Russia (Siberia), Sikkim, Tajikistan, Thailand, Turkmenistan, Uzbekistan, Vietnam; N Africa, Australia, Europe, North America].