Spilanthes

Annual, rarely perennial herbs, often prostrate and rooting at nodes, often in damp places. Leaves opposite, simple, ovate to linear, entire or sinuate, glabrous. Capitula radiate, many-flowered, usually on long peduncles, terminal or axillary. Involucre campanulate; bracts in 2 or 3 rows, outer membranous, shorter than receptacle. Receptacle convex, sometimes elongated, paleate; paleae boat-shaped, enclosing florets. Ray florets female, fertile; corolla yellow or white, strap-shaped; tube +/- hairy, with elliptic, usually 2-lobed lamina somewhat longer than tube. Disc florets bisexual, fertile; corolla yellow, tubular below, expanded above, 4- or 5-toothed. Anthers with small, obtuse apical appendage, base obtuse or minutely sagittate. Style branches of ray florets linear, of disc florets oblong, truncate, minutely penicillate. Cypselas elliptic or obovate, 3- or 4-angled, +/- compressed, margins hyaline or ciliate. Pappus 0 or of 2 or 3 bristles. x = 13 (6, 7, 9) (aneuploids, polyploidy).