Subshrubs, or perennial herbs with a woody caudex and ±erect or scandent annual stems, rarely annuals. Leaves simple, opposite, sessile or petiolate, uborbicular, ovate, lanceolate or linear, usually serrate, rarely entire or subpinnatisect, 3-nerved; base attenuate or rounded. Capitula terminal, solitary or in dichasial groups of up to 5 (–11), on short or long peduncles, radiate; involucral bracts in c. 2 series, (linear) lanceolate to ovate, green, rigid; receptacle paleaceous; paleae ±lanceolate, rigid, midribbed, acute to acuminate, dorsally scabrous. Ray florets female, fertile; ligule 2-or 3-lobed, yellow. Disc florets bisexual; corolla 5-lobed, yellow to yellow-orange; anther sacs yellow to pale yellow-brown. Achenes oblong to obovoid, sometimes winged, apically shortly pilose; ray achenes 3-angled; disc achenes 2-or 4-angled, compressed or not, the angles sometimes obscure (A. cylindrica) or expanded into corky or membranous wings. Pappus rarely entirely absent, usually a ring of tiny hairs and/or scales, sometimes with 1–3 weak and deciduous fragile awns.
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