Erect annual to biennial herb, up to 1.5 m tall. Stems ridged, sparsely hispid, becoming almost glabrous below. Cauline lvs elliptic to narrow-oblanceolate or linear, flat, apetiolate and cuneate, acute, entire, remotely serrate, or shallowly 1-pinnatifid, usually almost glabrous except for short cilia, sometimes sparsely to moderately scaberulous, 40-80-(120) × 3-10-(20) mm; uppermost lvs smaller, often ± linear. Infl. a long, leafy pyramidal panicle with dominant main axis. Capitula 1.5-2.5 mm diam.; receptacle with raised flanges between pits. Inner involucral bracts narrow-triangular, green, later tinged purple, glabrous, 3.2-4 mm long; outer bracts glabrous or with few hairs or ciliate. Outer florets filiform or with inconspicuous ligules < 0.5 mm long, cream, later tinged purple. Achenes obovoid-cylindric, sparsely hairy, 1.2-1.4 mm long; pappus hairs cream.