Plants annual, rarely biennial [perennial], glabrous or very weakly short-papillose, mostly in inflorescence and on leaf blades, with fusiform, vertical rootstock. Stems erect (some dwarf alluvial forms may be ascending or almost prostrate), branched in distal 2/3, occasionally almost near base, (5–)15–75(–100) cm. Leaves: ocrea deciduous to partially persistent at maturity; blade lanceolate or lanceolate-linear, rarely oblong-lanceolate, usually very gradually narrowed at both ends, (4–)7–25(–40) × (1–)1.5–4(–5) cm, at least 4 times as long as wide, base narrowly cuneate, very rarely broadly cuneate, margins entire, flat or rarely weakly undulate, apex acute, very rarely subobtuse. Inflorescences terminal, occupying distal 1/2 of stem, occasionally most of stem, golden or greenish yellow, usually rather dense or interrupted in proximal part, broadly paniculate, branches spreading. Pedicels articulated near base or at least in proximal 1/3, filiform, 3–8 mm, articulation weakly evident. Flowers 15–30 (occasionally more) in rather dense whorls; inner tepals narrowly triangular or narrowly rhombic-triangular, 2.5–3(–3.5) × 0.75–1.2(–1.5) mm (excluding teeth), normally ca. 2 times as long as wide, base truncate or broadly cuneate, margins prominently dentate, apex acute, very rarely subacute, straight, teeth 2–3(–4), normally at each side of margins, subulate-filiform, bristlelike, 1–3.5 mm, usually 1.5–2 times as long as width of inner tepals; tubercles 3, equal or subequal, apex acute or subacute, smooth. Achenes light brown, small, 0.9–1.75 × 0.6–1 mm. 2n = 40.