Perennials or shrubs (sometimes scandent), 20-250 cm (fibrous-rooted). Stems erect or clambering, sparsely to densely branched. Leaves cauline; opposite [alternate, verticillate]; petiolate or sessile; blades usually 3-nerved from bases, mostly deltate to ovate or elliptic, sometimes linear, margins dentate or lobed, faces glabrous or puberulent to tomentose, sometimes gland-dotted. Heads discoid, in corymbiform to thyrsiform arrays. Involucres cylindric [campanulate to hemispheric], 2-7 mm diam. Phyllaries usually readily falling (at least in fruit), 18-65+ in 4-6+ series, 3-5-nerved, ovate to oblong or lanceolate, unequal (papery or herbaceous). Florets [6-]15-40[-75]; corollas white or purple to blue, lavender, or reddish, throats cylindric (lengths 3-4 times diams.); styles: bases not enlarged, glabrous, branches linear to linear-clavate. Receptacles flat to convex, paleate or epaleate. Cypselae prismatic, (3-)5-ribbed, scabrellous, usually gland-dotted as well; pappi persistent, of ca. 40 barbellate bristles in 1 series. x = 10.
