Perennials, 20-150 cm; usually rhizomatous and/or lignescent-tuberous-rooted. Stems erect, simple, internodes winged (by decurrent leaf bases), lanate-tomentose and/or glandular. Leaves cauline, alternate; sessile; blades linear to elliptic or obovate, bases decurrent, margins usually serrate to serrulate or denticulate, rarely entire, abaxial faces densely whitish-tomentose [puberulent or glabrescent], adaxial (green) glabrous or glabrescent, both faces usually stipitate- or sessile-glandular. Heads disciform, (sessile) in spiciform arrays (at ends of branches). Involucres cylindro-campanulate to campanulate, 2-3[-5] mm diam. Phyllaries persistent, in 4-6 series, distinct, narrowly lanceolate, unequal (subindurate to scarious). Receptacles flat, epaleate. Ray florets 0. Peripheral (pistillate) florets in 1-3+ series, fertile; corollas yellowish. Inner (functionally staminate [bisexual]) florets [1-]2-15[+]; corollas yellowish, lobes 5. Cypselae cylindric to fusiform, angled or slightly compressed, ribs 6-9 (white, narrow), faces usually sparsely strigose to hispidulous, minutely sessile-glandular between ribs; pappi persistent, of distinct, barbellulate bristles in 1-2 series. x = 10. The 11 primarily South American species of Pterocaulon sect. Pterocaulon have 1-17 functionally staminate florets per head, 1-2-seriate pappi, and hairs of tomentum with the relatively long, aseptate portion arising from clusters of basal cells. The 6 Australasian species of sect. Monenteles (Labillardière) Cabrera have a single functionally staminate floret per head, uniseriate pappi, and hairs of the tomentum equally septate throughout.