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 10–18 blunt ridges when dry, 10–50 cm × 0.3–2 mm, firm to rigid, 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 brown or reddish, distally stramineous, brown, reddish or green, often inflated, papery, apex mostly dark red-brown, subtruncate to obtuse, often callose, tooth absent.

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, 3–8 × 2–2.5 mm, apex acute;

proximal scale amplexicaulous, entire;

subproximal scale empty or with flower;

floral scales appressed in fruit, 10–20, 3 per mm of rachilla, orange-brown, midrib regions often greenish, ovate, 3–3.5 × 1.5 mm, apex entire, 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 6, stramineous, stout, nearly equal, mostly equaling or exceeding tubercle, (0.5–)1–2.2 mm, prominently retrorsely spinulose;

stamens 3(?);

anthers dark yellow to stramineous, 1.2–1.5;

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.

falling with scales, dark brown, obpyriform, nearly eqilaterally- to greatly compressed-trigonous, angles slightly prominent, 1–1.3 × 0.75–0.9 mm, neck absent or short, finely rugulose at 20X with more than 20 horizontal ridges in vertical series, or reticulate or 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.

well developed, whitish, pyramidal, as high as wide to much lower than wide, 0.2–0.6 × 0.4–0.7 mm.