Flora of North America species comparison

terete, often with some blunt ridges when dry, (5–)10–60 cm × 0.2–1.5 mm, firm, internally spongy.

terete or cross section elliptic (or rectangular), usually with to 8 blunt ridges when dry, 10–50 cm × 0.2–0.7(–1) mm, soft to firm, spongy.

distal leaf sheaths persistent, not splitting, proximally red, distally stramineous to green, often callose, thinly papery to thickly membranous, apex often dark red-brown, obtuse to subacute, tooth absent.

distal leaf sheaths persistent, not splitting, mostly proximally dark red, distally red to brown or green, thinly papery to thickly membranous, apex usually redbrown, subtruncate to obtuse or subacute, callose, tooth often present on most or all culms, to 1 mm.

ovoid to lanceoloid, 5–10 × 2–3(–4) mm, apex acute;

proximal scale amplexicaulous, entire;

subproximal scale with flower;

floral scales often spreading in fruit, 10–20, 3–4 per mm of rachilla, brown to often red-brown, midrib regions mostly stramineous to green, broadly ovate, 3–4 × 1.8–2.5 mm, entire, apex acute to obtuse, often some carinate in distal part of spikelet.

narrowly lanceoloid (to narrowly cylindric), 3–20 × 1.5–2.5 mm, apex acute;

proximal scale amplexicaulous, entire;

subproximal scale empty or with flower;

floral scales appressed or spreading in fruit, 15–40, 3–4 per mm of rachilla, orange brown, midrib regions often greenish, ovate, 2–3 × 1 mm, apex entire, rounded to obtuse in proximal part of spikelet, acute in distal part, carinate, at least in distal part of spikelet.

perianth bristles 0–4(–5), light brown to stramineous, stout, usually unequal, rudimentary to equaling achene;

stamens 3;

anthers dark yellow to stramineous, 1.2–2 mm;

styles 2-fid.

perianth bristles 3–7, rarely apparently absent, stramineous to whitish, slender to stout, often unequal, rudimentary to slightly exceeding tubercle;

stamens 3;

anthers yellow to stramineous, 1.1–2 mm;

styles 3-fid, 0.3–0.4 × 0.2–0.3 mm.

not persistent, dark yellow or medium or dark brown, ellipsoid, obovoid, or obpyriform, biconvex, angles obscure, 1.3–1.8 × 1–1.4 mm, apex rounded, neck absent or short, smooth at 30X, or sometimes finely rugulose at 10–20X with 20 or more horizontal ridges in vertical series.

falling with scales, yellow-brown or dark brown, ellipsoid or obovoid to obpyriform, compressed-trigonous, angles evident to obscure, rarely prominent, 0.8–1.4 × 0.5–0.7 mm, neck absent to long, smooth or sometimes minutely cancellate at 20–30X.

brown to whitish, pyramidal, much higher than wide to slightly depressed, sometimes spongy and with vertical rows of depressions, 0.4–0.8 × 0.3–0.8 mm.

whitish, pyramidal, often higher than wide, 0.3–0.4 × 0.25–0.35 mm.

= 10.