Flora of North America species comparison

terete, often with 8–12 blunt ridges when dry, 8–80 cm × 0.3–1.4 mm, firm to soft, internally 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 red (to stramineous), distally green to stramineous, usually inflated, often callose, membranous to papery, apex often red-brown, broadly obtuse to subacute, tooth sometimes present, to 0.1 mm.

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

ovoid to lanceoloid or nearly cylindric, 3–18 × 2–3(–4) mm, apex acute (to obtuse);

proximal scale amplexicaulous, entire;

subproximal scale with flower;

floral scales often spreading in fruit, 15–50, 4–5 per mm of rachilla, medium brown to sometimes red-brown, midrib regions mostly stramineous to green, in proximal part of spikelet ovate, apex rounded, in distal part lanceolate, apex entire, acute, 2–3.5 × 1.5–1.7 mm, mostly carinate.

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 4 or absent, light brown to stramineous, stout, usually equal, equaling achene to slightly exceeding tubercle;

stamens 3;

anthers dark yellow to stramineous, 1–1.8 mm, apiculate;

styles 2-fid.

perianth absent;

stamens 1;

anthers 0.2–0.3 mm;

styles 3-fid.

not persistent, dark yellow, stramineous, or dark brown, obovoid to obpyriform, biconvex, angles obscure, 0.9–1.6 × 0.7–1.2 mm, apex rounded, neck absent to long, smooth at 30X, or sometimes finely rugulose at 10–30X with 20 or more horizontal ridges in a vertical series.

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.

brown to whitish, pyramidal, much higher than wide to, lower than wide, 0.35–0.65 × 0.2–0.6 mm.

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

= 16, 18, 19, 20.