Flora of North America species comparison

present, caudexlike, mostly concealed by crowded culms, vertical or ascending, 2 mm thick;

internodes very short, scales disintegrating to fibers, 4 mm, papery.

subterete, often with to 6 prominent ridges when dry, sulcate, 10–30 cm × 0.3–0.5 mm, firm to rigid, spongy.

erect to ascending or arching, acutely quadrangular, deeply sulcate, 7–50 cm × 0.3–0.5 mm, smooth, firm.

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, proximally brown or reddish, distally stramineous to green, thickly membranous, apex acute or subacute.

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.

basal spikelets absent; often proliferous, ovoid, terete, 3–10 × 2–3 mm, apex acute;

proximal scale empty, amplexicaulous, similar to floral scales;

subproximal scale with a flower;

floral scales spiraled, 8–15, 4 per mm of rachilla, orange-brown, midrib region broadly stramineous or like flanks, ovate, 2–3 × 1.2–2 mm, membranous, midrib evident to prominent, apex acute (to rounded).

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 or fewer, stramineous, unequal, some or most equaling achene, spinules obscure, sparse, retrorse, sharply acute.

3;

anthers 1.2–1.5 mm.

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.

stramineous, broadly obpyriform, equilaterally trigonous, angles evident, blunt, 0.9–1.1 × 0.7–0.9 mm, apex nearly truncate, smooth or obscurely papillose or rugulose at 20X.

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

stramineous, pyramidal, trigonous, usually acute, proximally trilobed, the lobes decurrent on achene, 0.5–0.9 × 0.7–0.9 mm.