Annual (or biennial?), stout, erect, ± glabrous. Stem sulcate, hollow, often much branched. Leaves petiolate, basal leaves 3-lobed or 3-partite, lateral lobes sometimes deeply bilobed again, lobes irregularly shallowly crenate. Upper stem leaves sessile, 3-lobed, lobes linear-oblong, entire or ± deeply crenate to lobulate. Flowers numerous, 5-10 mm in diameter, yellow. Sepals pubescent outside, ovate, obtuse, deflexed, petals shorter than sepals, obovate. Achenes up to 1.3 mm, glabrous, smooth to rugose, dorsally keeled, arranged in an oblong to shortly cylindrical spike, attached to a sparsely ciliate elongated, spindle-shaped receptacle. Style very short, asymmetrically inserted, with an obtuse tip.