1. Cinna arundinacea L. (wood reed, wood reed grass)

Pl. 134 j, k; Map 542

C. arundinacea var. inexpansa Fernald & Griscom

Plants perennial, with rhizomes lacking or very short, forming tufts or small clumps. Flowering stems 50–170 cm long, erect, sometimes from spreading bases, sometimes swollen and somewhat bulblike at the base, glabrous. Leaf sheaths rounded on the back, glabrous, the ligule 3–11 mm long, often somewhat torn or irregularly lobed. Leaf blades 9–35 cm long, 6–15 mm wide, flat, usually roughened along the margins and sometimes also on the upper surface. Inflorescences 10–35 cm long, usually dense panicles with strongly ascending to spreading branches, erect or somewhat drooping. Spikelets 3.7–6.5 mm long, strongly flattened laterally, disarticulating below the glumes, with 1 perfect floret and without additional staminate or sterile florets. Lower glume 3.2–5.6 mm long, shorter than the lemma, lanceolate, sharply pointed at the tip, 1‑nerved, keeled, awnless, roughened, sometimes only along the midnerve. Upper glume 3.7–6.5 mm long, usually slightly longer than the lemma, lanceolate, sharply pointed at the tip, 3‑nerved, keeled, awnless, roughened. Lemma 3.0–5.5 mm long, papery, lanceolate, sharply pointed at the tip, 3‑nerved, keeled, awnless or more commonly with an awn 0.2–1.5 mm long attached less than 1 mm behind the tip, roughened, the base glabrous. Palea 2.4–4.5 mm long, membranous, usually 1‑nerved. Stamen 1 per floret, the anther 0.8–1.9 mm long. Fruits 2–3 mm long, narrowly elliptic in outline, yellowish brown. 2n=28. July–October.

Scattered to common nearly throughout Missouri (eastern U.S. and adjacent Canada west to North Dakota and Texas). Bottomland forests, mesic upland forests in ravines, banks of streams and spring branches, shaded margins of ponds and sloughs, fens, and acid seeps, rarely margins of glades; also margins of pastures.