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.

sometimes decumbent, in same plant sides variably smooth or with 1 to few acute ridges (often nearly smooth or with 1 ridge on 1 side and several ridges on the other), greatly compressed, usually inrolled when dry, rectangular in cross section, 10–40 cm × 0.3–1.5 mm, 0.2–0.5 mm thick, firm, margins often sharply acute, margins and often 1 or more ridges minutely serrulate at 20–30X.

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, red proximally, colorless or stramineous or whitish distally, slightly inflated, thickly membranous, apex acute.

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.

ovoid or lanceoloid, 3–9 × 1.5–2.5 mm, apex acute;

floral scales 15–30, 6 per mm of rachilla, orange-brown or often stramineous or colorless, midrib region stramineous or greenish, ovate-lanceolate, (2.2–)2.7–3.2 × 1.5 mm, midrib prominent, apex acute.

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 absent;

anthers 1.1–1.75 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.

compressed-trigonous, with angles plus longitudinal ridges ca. 9–13, prominent, obovoid, mostly 2 times longer than wide, 0.7–0.9(–1.1) × (0.4–)0.5 mm, trabeculae 30–60, rather obscure and crowded.

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.

brownish, pyramidal, usually depressed, 0.1–0.15 × 0.2–0.25 mm.