Flora of North America species comparison

terete or cross section elliptic or rectangular, with 5–10 blunt ridges when dry, 25–50 cm × 0.5–1.2 mm, firm to hard, spongy.

terete, often with a few blunt ridges when dry, 20–50 cm × 0.2–0.7 mm, soft, spongy.

distal leaf sheaths persistent, not splitting, mostly proximally dark red, distally red to brown or green, thinly papery, apex usually red-brown, often callose, subtruncate to obtuse, tooth usually present on some or all culms, to 0.9 mm.

distal leaf sheaths persistent, not splitting, proximally red or stramineous, distally green, membranous, apex usually reddish, subtruncate to obtuse, not callose, tooth present, to 0.4 mm.

usually ovoid or ellipsoid to subcylindric, rarely lanceoloid, 4–12 × (1.5–)2–3 mm, apex rounded to acute;

proximal scale amplexicaulous or clasping over 3/4 of culm, entire;

subproximal scale empty or with flower;

floral scales appressed in fruit, 30–100, 6–10 per mm of rachilla, orange-brown, midrib regions often greenish, oblong to ovate, 1.5–2.5 × 1–1.5 mm, apex entire, broadly rounded, sometimes acute in distal part of spikelet, usually horizontally wrinkled and recurved, often carinate in distal part of spikelet.

narrowly lanceoloid, narrowly ovoid, or narrowly cylindric, 4–10 × 1–1.5 mm, apex narrowly acute;

proximal scale amplexicaulous or clasping 3/4 of culm, entire;

subproximal scale empty or with flower;

floral scales spreading in fruit, 20–80, 5–6 per mm of rachilla, orange-brown, midrib regions stramineous, narrowly ovate-lanceolate, 1.5–2 × 0.8 mm, entire, apex acute, not carinate.

perianth bristles 5–6(–7), stramineous to medium brown, stout, often unequal, much shorter than to equaling achene, rarely all rudimentary;

stamens 3;

anthers dark yellow to stramineous, 0.8–1.5 mm;

styles 3-fid or some 2-fid.

perianth bristles 3–6, stramineous, stout, unequal, rudimentary to less than 1/2 achene length;

stamens 3;

anthers stramineous, 0.7–1.4 mm;

styles 3-fid.

falling with scales, dark brown, obovoid to obpyriform, compressed trigonous, angles evident to obscure, 0.7–1 × 0.65–0.8 mm, neck absent to sometimes long, finely rugulose at 10–30X, over 20 horizontal ridges in vertical series, and/or minutely cancellate at 20–30X.

falling with scales, stramineous, ellipsoid, compressed-trigonous, angles prominent (keeled), 0.6–0.65 × 0.4–0.45 mm, base narrowed, neck long, smooth at 40X.

brown to whitish, pyramidal, as high as wide or sometimes greatly depressed, (0.1–)0.25–0.3 × 0.2–0.3 mm.

brown, pyramidal, as high as wide to greatly depressed, 0.1–0.25 × 0.15–0.2 mm.

= 20.