Coreopsis

Perennial herbs. Leaves opposite, rarely alternate, entire, lobed or dissected. Capitula radiate, pedunculate, solitary or in lax corymbs. Involucre with bracts in 1 or 2 rows. Receptacle flat or slightly convex, paleate. Ray florets neuter or female, fertile or sterile; corolla yellow, strap-shaped. Disc florets bisexual, fertile or inner ones functionally male; corolla yellow, cylindric or narrowly campanulate, 5-toothed. Anthers with bases obtuse or minutely sagittate. Style with branches of disc florets truncate, penicillate or with subulate appendage. Cypselas compressed, often winged or with spiny or cartilaginous margins. Pappus of (1)2 barbed or nude awns or scales. x = 6, 13 (7, 9, 10) (aneuploids, high polyploidy).