Calamagrostis arundinacea is a species of bunch grass in the family Poaceae, native to Eurasia, China and India. The species is perennial and tufted with short rhizomes and erect culms that are 60–150 centimetres (24–59 in) long. Each leaf has a truncate ligule which is 2–4 millimetres (0.08–0.16 in) long, and obtuse. The leaf-blades are 8–50 mm (0.3–2.0 in) by 1.8–10 mm (0.07–0.39 in), hairless and have both a scabrous surface and an attenuate apex. The panicle has a scaberulous peduncle and is lanceolate, open, continuous, and is 8–18 cm (3.1–7.1 in) long by 1–4 cm (0.4–1.6 in) wide. Flowers have a pair of lodicules and stigmas, and three anthers which are 2.4–2.7 mm (0.09–0.11 in) long. The fruit is a caryopsis with an additional pericarp.