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.

terete, often with to 12 blunt ridges when dry, 30–75 cm × 0.5–1.5 mm, firm, internally spongy.

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, not splitting, proximally dark red, distally stramineous or green, papery to membranous, apex dark redbrown, obtuse, not callose, tooth rarely present on some culms, 0.2 mm.

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.

ovoid or subspheric, 5–12 × 2–3(–4) mm, apex acute to obtuse;

proximal scale amplexicaulous, entire;

subproximal scale with flower;

floral scales deciduous, often spreading in fruit, 10–35, 3 per mm of rachilla, red-brown to blackish brown, midrib regions sometimes green, ovate, 2.5–3 × 1.7 mm, apex entire, obtuse to acute, often carinate in distal part of spikelet.

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 bristles 1–5, brown, stout, very unequal, rudimentary to equaling achene;

stamens unknown [absent from specimens];

styles 3-fid or some 2-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.

not persistent, dark yellow or medium brown, obovoid to obpyriform, compressed trigonous, or some thickly biconvex, angles evident, 1.1–1.5 × 0.95–1.25 mm, apex rounded, neck very short (to absent), finely rugulose at 10–20X, 20 or more horizontal ridges in vertical series, finely cancellate at 20–30X.

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

whitish to brown, pyramidal, not depressed, as high as wide, 0.3–0.5 × 0.4–0.6 mm.

= 42.