Annuals, biennials, perennials, or subshrubs, 15-250 cm (taprooted, rhizomatous in G. oölepis). Stems (1-6) usually erect, sometimes ascending or decumbent to prostrate, simple or branched, glabrous or hairy, often gland-dotted and/or resinous. Leaves basal and cauline or mostly cauline; alternate; petiolate (proximal) or sessile (distal); cauline blades 1-nerved, oblong, obovate, oblanceolate, or spatulate to triangular, lanceolate, or linear (bases usually clasping), margins usually serrate to dentate, sometimes entire, crenate, or pinnatifid (especially proximal), faces usually glabrous and gland-dotted, sometimes hirsutulous, hirtellous, puberulous, scabridulous, villous, or stipitate-glandular. Heads radiate or discoid, in corymbiform to paniculiform arrays or borne singly. Involucres usually globose to hemispheric or broadly urceolate, sometimes campanulate to obconic, 5-25 mm diam. (excluding phyllary apices). Phyllaries (persistent) 25-100+ in (3-)4-9 series, 1-nerved or obscurely so (± flat, proximally and/or medially thickened), mostly filiform, linear, or lanceolate, usually unequal, sometimes subequal, bases usually ± chartaceous (apices ± herbaceous, looped, hooked, patent, recurved, straight, or incurved), abaxial faces usually glabrous and ± resinous. Receptacles flat or convex, ± pitted (pits sometimes flanked by membranous or setiform enations), epaleate. Ray florets 0 or 5–60, pistillate, fertile; corollas yellow to orange. Disc florets (20-)100-200(-300), bisexual and fertile (all or outer) or functionally staminate (ovaries not producing cypselae) corollas yellow, tubes shorter than gradually to abruptly ampliate throats, lobes 5, erect or spreading, ± deltate (equal); style-branch appendages linear or lanceolate to ± deltate. Cypselae (whitish or stramineous to gray, brown, or reddish) ellipsoid to obovoid, ± compressed, sometimes ± 3-4-angled (apices smooth, coroniform, or knobby), faces smooth, striate, ribbed, furrowed, or rugose, glabrous; pappi falling, of (1-)2-8[-15], straight or contorted to curled, smooth or barbellulate to barbellate, sometimes distally clavate, subulate scales, setiform awns, or bristles in 1 series (in G. ciliata, persistent or tardily falling, of 25-40 barbellate bristles subtending 8-15+ barbellate, setiform awns or subulate scales). x = 6.