Annuals, perennials, or subshrubs [shrubs], (20-)30-70[-250+] cm. Stems erect, branched from bases or throughout. Leaves cauline; mostly opposite (distal sometimes alternate); petiolate or sessile; blades (or lobes) ovate, oblanceolate, or linear, 1-pinnately lobed, ultimate margins ± toothed (teeth often bristle-tipped), faces glabrous or ± hirtellous to scabrellous (oil-glands usually borne at bases of lobes and subterminally near apices). Heads usually radiate, rarely discoid, borne singly. Calyculi of 3-5 or 12-22 linear to subulate bractlets (sometimes with 1-2 lobes, often bristle-tipped, usually bearing oil-glands). Involucres campanulate to obconic [hemispheric], [5-]7-20+ mm diam. Phyllaries persistent, 8-20+ in ± 2 series (weakly connate 1/3-3/4 their lengths, separating in age, mostly lanceolate to linear, margins of outer distinct to bases or nearly so, oil-glands in faces and near margins). Receptacles convex, ± pitted (socket margins fimbrillate to setose), epaleate. Ray florets usually 7-16[-16], rarely 0, pistillate, fertile; corollas yellow to orange or red-orange. Disc florets 25-70[100+], bisexual, fertile; corollas yellow to yellow-orange, tubes shorter than cylindric throats, lobes 5, lance-ovate to lance-linear. Cypselae obpyramidal [obconic], glabrous or ± strigose or sericeous; pappi persistent, of 8-20 scales in 1-2 series (single scales muticous, or unequally 3-aristate, or comprising 5-11 basally connate bristles). x = 7, 13.
