Calamagrostis expansa is a robust, short-rhizomatous perennial with erect or decumbent culms, 0.5 to 2 m (1.6 to 6.6 ft) tall and 4 to 8 mm (0.16 to 0.3 in) in diameter. Sheaths are 3.5 to 4 mm (0.14 to 0.16 in) long and overlap closely along the middle of the culm. Leaf blades are flat to involute...