Perennials [annuals], 30-150 cm. Stems erect or trailing, branched from bases or ± throughout. Leaves cauline; opposite; petiolate; blades ± 3-nerved from bases, deltate or ovate to lanceolate, bases ± cuneate to subtruncate, margins serrate or coarsely toothed, faces glabrous or hairy. Heads radiate [discoid], borne singly. Involucres turbinate to hemispheric, 8-14 mm diam. Phyllaries persistent, 12-20 in 2-3 series (ovate or oblong, ± equal, outer more foliaceous than inner). Receptacles convex to conic, paleate (paleae tardily falling, yellowish, conduplicate, becoming chartaceous). Ray florets [0] 5-20, pistillate, fertile; corollas yellow to orange (laminae persistent, sessile, becoming papery). Disc florets 30-150+, bisexual, fertile; corollas yellow or brown to purple, tubes much shorter than narrowly cylindric throats, lobes 5, deltate. Cypselae (brown to black-brown) subterete or obscurely 3(ray)- or 4(disc)-angled (not winged); pappi 0, or persistent, coroniform (each a laciniate crown plus 1-3 toothlike scales). x = 14. Most species of Heliopsis are known only from Mexico.