Description from Flora of China
Verbesina acmella Linnaeus, Sp. Pl. 2: 901. 1753; Blainvillea latifolia (Linnaeus f.) Candolle; Eclipta latifolia Linnaeus f.; Spilanthes acmella (Linnaeus) Murray.
Herbs, annual. Stems erect, 40-60 cm tall, branched. Lower leaves opposite, with up to 1 cm petioles, blade ovate to ovate-lanceolate, 3-6 × 2-3 cm, both surfaces scabrid, base cuneate, margin sparsely serrate, apex acuminate; upper leaves smaller, usually alternate, ovate to ovate-oblong, 2-3 × 1.3-1.5 cm, base usually rounded. Capitula axillary or terminal, ca. 1 cm in diam.; peduncles slender, 15-40 mm, with spreading hairs; phyllaries 2-seriate, outer papery, green, ovate-oblong, ca. 6 mm, dorsally densely hairy, apex shortly acute or obtuse, inner ovate to oblong-linear, ca. 5 mm, sparsely pubescent, apex acute; paleae oblong-lanceolate, ca. 5 mm, dorsally pubescent, apex aristiform. Ray florets 1-seriate, yellow or yellowish white, lamina ca. 3 mm, apex 2-4-toothed. Disk florets campanulate, limbs 5-toothed. Achenes densely pubescent, those in female florets 3-angled, ca. 4 mm, those in bisexual florets compressed, ca. 5 mm; pappus short, unequal, 2-5. Fl. Apr-Jun.
Open broad-leaved forests, grassy slopes; below 2600 m. Hainan, Sichuan, Yunnan [India, Indonesia, Malaysia, Myanmar, Nepal, Philippines, Thailand, Vietnam; Africa, Australia, South America].