87. Aster tricephalus C. B. Clarke, Compos. Ind. 43. 1876.
三头紫菀 san tou zi wan
Herbs, perennial, 30-40 cm tall, rhizomatous, often with robust stolons bearing rosettes. Stems erect, simple below, sparsely pilose. Leaves basal and cauline, pilose, glandular, basal leaves (flowering stems) absent or withered by anthesis; blade spatulate, ca. 6.5 × 2 cm; cauline leaves ± evenly distributed and similar in size, usually overlapping, sessile, oblanceolate, elliptic, or lanceolate, 3.5-6.5 × 0.6-2.1 cm, base subclasping, margin entire or 2- or 3-serrulate, apex obtuse or acute; upper leaves often surrounding capitula. Capitula 1-3 (rarely more), 2-2.8 cm in diam. Involucres not described; phyllaries 1- or 2-seriate, leaflike, oblanceolate, 12-14 × 2-3 mm, glabrate, midvein brownish, ciliate, apex acute or obtuse. Ray florets 50-60, white or blue, tube ca. 0.2 cm, lamina ca. 18 mm; disk florets yellow, 4.5-5.5 mm, hairy, tube 1.5-2 mm, lobes ca. 1.5 mm. Achenes brown, obovoid, 3.4-4 mm, strigillose, apically glandular, 2-ribbed. Pappus whitish or buff, 5-5.5 mm. Fl. Aug-Oct.
3600-4000 m. S Xizang [India (Sikkim), Nepal].
Aster tricephalus is similar in height to A. barbellatus and A. neoelegans but differs in its flowering stems without basal leaves, the basal leaves being present only on well-developed stolons, its capitula usually 3, and its ray florets 50-60.