Herbs annual, yellow-green, 20-50 cm tall, with a strong odor, covered with stalked, glandular hairs. Stem erect, mostly branched from base. Petiole 2-10 mm; leaf blade oblong, 2-4 × 1-2 cm, base cuneate, margin pinnately parted, apex subobtuse, sometimes mucronulate; lobes obtuse, usually obtusely toothed; upper leaves lanceolate, smaller, margin entire. Compound dichasia axillary, forming tower-shaped panicles on upper branches. Flowers bisexual. Perianth segments (4 or)5, erect in fruit, yellow-green, oblong, abaxially glandular, not longitudinally keeled or only weakly keeled, margin membranous, apex subobtuse or acuminate. Stamens 1-3. Stigmas 2, filiform. Utricle depressed globose; pericarp whitish, membranous . Seed horizontal, black, sublustrous, depressed, 0.75-1 mm in diam., almost unpitted, rim margin obtuse, slightly sulcate. Fl. Jul-Aug, fr. Aug-Sep.
Stems erect to ascending, branched at base to ± simple, 1-6(-10) dm, pubescent with short-stalked glandular hairs. Leaves aromatic; petiole to 2.5 mm; blade 1.3-4 × 0.6-2.7 cm, base cuneate, margins lyrate-sinuate, pinnatifid, or occasionally entire (in distal leaves), apex acute to subobtuse, glandular-pubescent abaxially. Inflorescences axillary cymes, often arranged in terminal thyrses, 12-24 cm, subtended by cauline leaves; bracts absent. Flowers: perianth segments 5, distinct nearly to base, distinct portion elliptic or ovate to oblong, 0.7-1.1 × 0.5-0.7 mm, apex acute to obtuse, rounded abaxially, densely glandular-pubescent, covering fruit at maturity; stamens 1-3(-5); stigmas 2. Achenes subglobose; pericarp adherent, membranaceous, papillose, becoming rugose, usually white-blotchy. Seeds globose to subglobose, (0.5-) 0.6-0.8 × 0.5-0.7 mm, margins rounded (rarely indistinctly furrowed); seed coat rugose. 2n = 18.