Publ. Field Mus. Nat. Hist., Bot. Ser. 22: 399. 1940.
Perennials, 60–150+ cm (fibrous-rooted). Leaves cauline; opposite; petiolate or sessile; blades ± lanceolate to narrowly trullate, (bases sometimes ± auriculate) margins entire or denticulate, faces: abaxial glabrous, adaxial minutely scabrellous to hirtellous. Heads radiate, borne singly or in open, corymbiform arrays. Involucres ± campanulate or broader, 9–12+ mm diam. Phyllaries persistent, 14–18+ in ± 3 series (± oblong, ovate, ovate-oblong, or ovate-attenuate, unequal, outer shorter). Receptacles flat to convex, epaleate. Ray florets 6–8, pistillate, fertile; corollas yellow. Disc florets 20–30, all bisexual or inner functionally staminate; corollas yellow, tubes shorter than to equaling ± campanulate to funnelform throats, lobes 5, ovate-deltate to deltate (style branches stout, appendages deltate). Ray cypselae ± obovoid, weakly obcompressed, 16–24-nerved, ± hispidulous; pappi 0, or fragile, of 6–8+ barbellate bristles (borne on crowns). Disc cypselae ± ellipsoid to clavate, ± hispidulous; pappi 0, or fragile, of 6–8+ barbellulate bristles (borne on crowns).