裸冠菊 luo guan ju

Alomia spilanthoides D. Don ex Hooker & Arnott, Companion Bot. Mag. 1: 238. 1836.

Herbs, perennial, 1-1.5 m tall. Stems erect, few branched, glabrous, angled, fistulose. Leaves opposite, glabrous, broadly lanceolate to ovate; petiole ca. 2.5 cm; blade 8-12(-18) × 1-2.5(-9) cm, 3-veined or veins pinnate, base attenuate, rarely truncate, margin serrate, apex acute. Synflorescence terminal, cymose. Involucre hemispheric, ca. 4 × 8 mm; phyllaries 2-seriate, lanceolate, outside pubescent; receptacle convex; corollas white, ca. 4 mm, short-stipitate glandular throughout; style base lacking basal node, glabrous; style branches clavate to oar-shaped, white or pink. Achenes ca. 3 mm, 5-ribbed, body gland-dotted. Fl. and fr. Sep-Oct. 2n = 20.

Recently introduced, and now naturalized, in Guangxi, Taiwan, and Yunnan [native to South America; naturalized in Australia, Japan, and Pacific islands (New Zealand)].

Gymnocoronis spilanthoides is an emergent plant and prefers marshes or pond sides. It spreads by the stems, which easily produce roots.