鬼针草 gui zhen cao

Bidens chilensis Candolle; B. pilosa var. minor (Blume) Sherff; B. pilosa f. radiata Schultz Bipontinus; B. pilosa var. radiata (Schultz Bipontinus) J. A. Schmidt; B. pilosa f. rubiflora S. S. Ying; B. sundaica Blume var. minor Blume; Kerneria tetragona Moench, nom. illeg. superfl.

Annuals. Stems 30-180 cm tall, glabrous or very sparsely pubescent in upper part. Petiole 10-30(-70) mm; leaf blade either ovate to lanceolate, 30-70(-120) × 12-18(-45) mm, or pinnately 1-lobed, primary lobes 3-7, ovate to lanceolate, (10-)25-80 × (5-)10-40 mm, both surfaces pilosulose to sparsely hirtellous or glabrate, bases truncate to cuneate, ultimate margin serrate or entire, usually ciliate, apices acute to attenuate. Synflorescence of solitary capitula or capitula in lax corymbs. Capitula radiate or discoid; peduncles 10-20(-90) mm; calycular bracts (6 or)7-9(-13), appressed, spatulate to linear, (3-)4-5 mm, abaxially usually hispidulous to puberulent, margins ciliate; involucres turbinate to campanulate, 5-6 × 6-8 mm; phyllaries (7 or)8 or 9(-13), lanceolate to oblanceolate, 4-6 mm. Ray florets absent or (3-)5-8; lamina whitish to pinkish, 5-15 mm. Disk florets 20-40(-80); corollas yellowish, (2-)3-5 mm. Outer achenes red-brown, ± flat, linear to narrowly cuneate, (3-)4-5 mm, faces obscurely 2-grooved, sometimes tuberculate-hispidulous, margin antrorsely hispidulous, apex truncate or somewhat attenuate; inner achenes blackish, ± equally 4-angled, linear-fusiform, 7-16 mm, faces 2-grooved, tuberculate-hispidulous to sparsely strigillose, margin antrorsely hispidulous, apex attenuate; pappus absent, or of 2 or 3(-5) erect to divergent, retrorsely barbed awns (0.5-)2-4 mm. Fl. year-round. 2n = 24, 36, 48, 72.

Roadsides, fields, villages; below 2500 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hebei, Henan, Hubei, Hunan, Jiangxi, Liaoning, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [tropical and subtropical regions].