Flora of North America species comparison

terete, often with 8–12 blunt ridges when dry, 20–55 cm × 0.3–1.3 mm, soft to hard.

erect, markedly spirally twisted, markedly obliquely contracted near spikelet, when dry often with to 6 broad, rounded ridges on each side, greatly compressed, 3–4 times as wide as thick, 20–40 cm × 1.5–2.5 mm, firm;

culm tufts not proximally bulbous.

distal leaf sheaths persistent, rarely splitting, proximally red to stramineous, distally green to reddish, papery, apex often dark reddish, subtruncate to obtuse, not callose, tooth present on some or all culms of plant, to 0.5 mm.

distal leaf sheaths stramineous to medium (or dark) brown, papery, apex often dark brown to reddish, broadly obtuse.

cylindric to ovoid, 5–20 × 2–3 mm, apex rounded to subacute;

proximal scale amplexicaulous, apex entire;

subproximal scale empty;

floral scales appressed in fruit, 20–200+, 10 per mm of rachilla, dark brown, midrib regions often stramineous or greenish, oblong, 1.7–2.5 × 1 mm, apex entire, broadly rounded, usually recurved, mostly carinate.

6–8 × 2–3 mm;

proximal scale empty, 3–4 mm, shorter than to equaling spikelet;

floral scales 8–10 per spikelet, 3.5–5 × 2 mm.

perianth bristles absent;

stamens 3;

anthers dark yellow, 1–1.5 mm;

styles 3-fid.

bristles 0–5, unequal, rudimentary to equaling achene, the shorter stout, smooth or nearly so, the longer slender, densely spinulose.

falling with scales, medium to dark brown, obovoid to obpyriform, with short neck, thickly trigonous, angles prominent (keeled), 0.7–0.9 × 0.4–0.6 mm, obscurely to clearly rugulose at 10–20X with more than 20 horizontal ridges in vertical series and/or minutely cancellate at 20–30X.

stramineous to medium brown, thickly trigonous, 1.75–2.75 × 1–1.25 mm;

beak 0.3–0.6 mm.

brown, rudimentary, mostly apiculate, sometimes pyramidal, 0.05–0.15 × 0.15–0.2 mm.

0.25–0.6 × 0.3–0.55 mm.

1.8 –3 mm.