Information

Annuals, to 200+ cm (delicate or robust, glabrate or glabrous). Stems erect. Leaves petiolate (proximal, petioles 10–20 mm) or sessile (distal); blades lanceolate or oblanceolate to elliptic or subovate, 30–150 × (7–)10–40 mm, bases (distal) connate, margins serrate, serrate-dentate, or spinulose-serrate. Heads 30–300+, in tight, axillary, sessile glomerules (receptacles of glomerules setose). Calyculi 0. Involucres oblong and cylindric or angular, 3.8–4.5 mm. Phyllaries usually 2, oblong (closely investing and falling with mature cypselae). Ray florets 0–1; laminae pale yellow or whitish, oblique or suborbiculate, 0.5–1 mm. Disc florets 0–1(–2); corolla tubes 0.5–1.4 mm, throats campanulate, 0.5–0.8 mm. Cypselae oblanceoloid to subclavate, 2–2.6 mm (rays longer); pappi 0. 2n = 36.