Helianthus

Annual or perennial herbs, erect. Leaves opposite, often alternate above, sessile to petiolate, simple, entire to dentate or serrate. Capitula radiate, in loose terminal cymes, or solitary, long-pedunculate; involucral bracts 2–4-seriate, subequal, herbaceous; receptacle convex to flat, pitted, with folded deciduous scales. Ray florets 1-seriate, female, fertile or sterile, ligulate, yellow. Disc florets bisexual, fertile, tubular; corolla campanulate, 5-lobed, yellow, brownish or purplish; anthers obtuse at base, apex with a triangular appendage; style bilobed, branches linear with acute narrow-triangular terminal appendages. Cypselas obovate to oblong, compressed, often emarginate at apex; pappus of c. 2 caducous scale-like awns, rarely small persistent scales also present.