Flora of North America species comparison

subterete, often with to 6 prominent ridges when dry, sulcate, 10–30 cm × 0.3–0.5 mm, firm to rigid, spongy.

sometimes ascending, subterete, elliptic, or polygonal, (1–)3–7.5(–9) cm × 0.2–0.5 mm, very soft.

distal leaf sheaths persistent, not splitting, proximally brown, red, or stramineous, distally stramineous, green or reddish, papery, apex sometimes reddish, obtuse, rarely callose, tooth absent.

distal leaf sheaths persistent or disintegrating, colorless, stramineous or green, spotted red-brown to purple, membranous, apex narrowly acute.

ovoid, 3–8 × 2–3 mm, apex acute to obtuse;

proximal scale amplexicaulous, entire;

subproximal scale with flower;

floral scales spreading in fruit, 8–30, 4–5 per mm of rachilla, dark brown to blackish, midrib regions often stramineous or greenish, ovate to lanceolate, 2–3 × 1.5 mm, apex entire, acute, often carinate in distal part of spikelet.

basal spikelets absent; never proliferous, ovoid or ellipsoid, terete, 2–4.7(–8.5) × 1–2 mm, apex acute to blunt;

proximal scale empty or with flower, persistent, clasping 1/2 of culm, similar to floral scales (but 1.1–1.7 mm, midrib region broadly green);

subproximal scale with a flower;

floral scales spiraled, 10–30(–100), 10–16 per mm of rachilla, colorless, whitish, or pale brown, mottled red-brown to purple, midribs pale brown or green, ovate or elliptic, 1–1.2 × 0.45–0.6 mm, membranous, midrib prominent, apex rounded.

perianth bristles 3–6, whitish to stramineous, stout to slender, often unequal, from rudimentary to 1/2 of achene length;

stamens 3;

anthers dark yellow to brown, 0.9–1.4 mm;

styles 3-fid.

perianth absent;

stamens 1;

anthers 0.2–0.3 mm;

styles 3-fid.

falling with scales, stramineous, rarely dark brown, ovoid to obpyriform, slightly to greatly compressed-trigonous, rarely thickly lenticular, angles prominent or abaxial angle obscure, 0.9–1.2 × 0.65–0.8 mm, apex narrowly to broadly truncate, neck short, often compressed more than body, at 20–30X finely rugulose with more than 20 horizontal ridges in a vertical series or reticulate or cancellate.

colorless (appearing green-brown from enclosed seed) or whitish, sometimes spotted red-brown, obovoid, trigonous, angles prominent, 0.5–0.6 × 0.33–0.4 mm, apex constricted proximal to tubercle, smooth.

whitish to brown, pyramidal, lower than wide, often 3-lobed as viewed from the top, 0.1–0.3 × 0.4–0.65 mm.

white, gray or pale brown, pyramidal or umbonate, trigonous, 0.1–0.15 × 0.15–0.2 mm.