丝棉草 si mian cao

Gnaphalium luteoalbum Linnaeus, Sp. Pl. 2: 851. 1753 ["luteo-album"]; Laphangium luteoalbum (Linnaeus) Tzvelev.

Herbs, annual, 15-40 cm, taprooted or fibrous-rooted. Stems loosely white tomentose, not glandular. Leaves crowded; internodes 1-5, sometimes to 10 mm; blade narrowly obovate to subspatulate, 1-3(-6) cm × 2-8 mm (distal smaller, oblanceolate to narrowly oblong or linear), both surfaces mostly concolorous to weakly bicolored, abaxially gray tomentose, adaxially usually gray tomentose, sometimes glabrescent, neither surface glandular, bases subclasping, usually decurrent 1-2 mm, margin weakly revolute. Capitula in terminal glomerules 1-2 cm in diam. Involucre broadly campanulate, 3-4 mm; phyllaries 3- or 4-seriate, silvery gray to yellowish, hyaline, ovate to ovate-oblong, glabrous. Female florets 135-160. Bisexual florets 5-10; corollas red tipped. Achenes not evidently ridged, conspicuously dotted with whitish, papilliform hairs. Pappus bristles loosely coherent basally, released in clusters or easily fragmented rings. 2n = 14, 28.

Exposed fields, roadsides; below 3200 m. Gansu, Hainan, Henan, Hubei, Jiangsu, Shaanxi, Shandong, Sichuan, Taiwan [Afghanistan, India, Laos, Pakistan, N Thailand, Vietnam; Africa, SW Asia (Iran), Australia, Europe, North America].