Annual; culms 15–180 cm. high, decumbent and rooting at the nodes below, robust and ascending or weak and rambling above.. Leaf-blades linear to narrowly lanceolate, 4–30 cm. long, 2–18 mm. wide; sheaths smooth on the nerves, or with tubercle-based hairs near the top.. Racemes 2–5 cm. long, axillary and distant or crowded into a false panicle.. Spikelets lanceolate-oblong, 2–3.3 mm. long; lower lemma abruptly acute, obtuse or minutely bidentate, with a slender awn 1–7 mm. long (rarely awnless); upper lemma obtuse or truncate, rarely mucronate.