Erect or decumbent annual, (15) 30–75 cm. tall, with numerous branches from the base upwards (or small plants unbranched below the inflorescence), vegetative parts glabrous or with scattered strigose hairs (especially along the margins and midrib of the upper leaves and on the upper internodes). Stem and branches strongly striate, subsulcate, or the basal internodes terete, nodes slightly swollen. Leaves linear, 3.5–12 × 0.2–1 cm., rather blunt at the apex with a distinct mucro formed by the confluence of the thickened margins and strong, excurrent midrib, attenuate and subsessile at the base. Inflorescences of axillary spikes c. 0.7 cm. wide and finally elongating to as much as c. 14 cm., on peduncles 0.2–6.5 cm. long, the upper often alternate; bracts deltoid-lanceolate, 1.5–2 mm. long, membranous except for the greenish, excurrent midrib, finally spreading; bracteoles similar but slightly smaller. Flowers sessile. Tepals green or sometimes suffused with red or brown, prominently 3-nerved and the nerves confluent with the midrib above but not excurrent in a mucro; outer 2 lanceolate-oblong, 3.5–4 mm. long, obtuse, with a very narrow hyaline border, shortly scabrid-pilose along the margins, nerves and often also between the nerves; inner 2 more broadly hyaline-bordered, the margins fringed with long, white hairs; middle tepal with one margin broadly hyaline and long-pilose, the other narrowly hyaline and scabrid. Stamens c. 2.5 mm. long, very delicate, almost free; pseudostaminodes none. Style c. 0.5 mm. long. Capsule ovoid, 2.75–3 mm. long. Seed ovoid, 1.5–2 mm., black, shining, faintly reticulate.
