24. Calamagrostis Adans. (reed bent grass)

Plants perennial, with well‑developed rhizomes, forming loose to dense clumps or colonies. Flowering stems erect, sometimes from spreading bases, glabrous or roughened. Leaf sheaths rounded on the back, glabrous or roughened, sometimes with a line of short hairs at the tip, the ligule often somewhat torn or irregularly lobed or toothed. Leaf blades flat or with inrolled margins, glabrous or roughened along the margins and the upper surface. Inflorescences open to dense panicles with strongly ascending to spreading branches, erect. Spikelets somewhat flattened laterally, disarticulating above the glumes, with 1 perfect floret and without additional staminate or sterile florets, the rachilla extended past the floret as a slender bristle. Glumes longer than the floret, similar in length and shape, rounded or somewhat keeled, awnless, the lower glume 1‑nerved, the upper glume 3‑nerved. Lemma thinner in texture than the glumes, lanceolate, sharply pointed or more commonly with 2 minute teeth at the tip, with an awn attached at or below the midpoint of the midnerve, 5‑nerved, glabrous or more commonly roughened, the base with a tuft of long, straight hairs, these more than 1/2 as long as the lemma. Palea slightly shorter than the lemma, membranous, 2‑nerved. Stamens 3, the anthers 1.0–2.5 mm long. Fruits oblong‑ovate in outline, yellowish brown. About 270 species, nearly worldwide, mostly in temperate regions.