Herbs annual, 20-60 cm tall. Stem erect or decumbent, slightly furfuraceous, ribbed and striate, branched above; branches slender, obliquely spreading. Leaves alternate or basal ones subopposite; leaf blade lanceolate to linear, 2-9 × 0.5-1 cm, both surfaces green and glabrous or slightly furfuraceous, base attenuate, margin irregularly curved serrate, sometimes subentire, apex subobtuse or acuminate. Inflorescences terminal, spicate or with short branches, usually forming a dense panicle. Male flowers: perianth 4- or 5-parted; stamens 4 or 5. Fruiting bracts connate below middle, rhombic to ovate-rhombic, ca. 3 × 2.5 mm, furfuraceous, sometimes distally with tuberculate processes, margins usually finely serrate distally, apex acute or shortly acuminate. Seeds of 2 types: black or red-brown, depressed globose or lenticular, 1-2 mm in diam., finely punctate. Fl. and fr. Aug-Oct.