Flora of North America species comparison

acutely quadrangular, (30–)45–105 cm × (1–)2–5.4 mm, soft to firm, internally spongy, transverse septa incomplete;

plants never forming filiform, flaccid culms.

terete, 2–15 cm × 0.15–0.3 mm, firm to soft.

distal leaf sheaths persistent, membranous, apex narrowly acute to acuminate, sometimes prolonged into a bladelike portion to 8 cm.

distal leaf sheaths persistent, not splitting, proximally stramineous to reddish, distally green or stramineous to reddish, membranous, apex often red, obtuse to acute, tooth absent.

not proliferous, (15–)20–76 × 3–5(–6) mm;

rachilla joints bearing obscure winglike remnants of floral scales;

proximal scale empty, amplexicaulous, (1–)2.2–5.4 mm;

floral scales (28–)45–135, 2–3 per mm of rachilla, stramineous to pale brown, usually with pale to dark brown submarginal band, midrib region sometimes greenish, broadly obovate to ovate, (4–)4.5–6.2 × 2.8–5 mm, subcartilaginous, apex rounded to obtuse.

ovoid, 1–4 × 1–2 mm, obtuse to acute;

proximal scale amplexicaulous, apex entire;

subproximal scale with flower;

floral scales spreading in fruit, 5–30, 8 per mm of rachilla, medium to very dark brown, midrib region often pale or greenish, broadly ovate, 1–1.3 × 1 mm, apex rounded, entire, not carinate.

perianth bristles 6–7, whitish to brown, slender, often markedly unequal, shorter than achene or some equalling tubercle, sparsely retrorsely spinulose to smooth;

anthers stramineous to red-brown, 2.3–2.9 mm;

styles 3-fid, sometimes 2-fid.

perianth bristles absent;

stamens 3;

anthers yellow, 0.3 mm;

styles 3-fid.

yellow or pale green to brown or purplish, biconvex, obovoid to obpyriform, 1.8–3 × 1.3–2 mm, almost smooth to markedly sculptured at 10–15X, each face with 19–38 rows of almost linear, transversely elongated cells, which are sometimes isodiametric at achene base, apex often constricted to neck 0.3–0.4 mm wide.

persistent after scales fall, to dark yellow-orange or brown, broadly obpyriform, trigonous, angles evident, 0.6–0.65 × 0.5–0.55 mm, rugulose at 20–30X, 20 blunt horizontal ridges in each vertical series.

dark brown or whitish, deltoid to high-pyramidal or lanceoloid, 0.7–1.5 × 0.4–1 mm, often spongy.

brown, greatly depressed, rudimentary, 0.05–15 × 0.15–0.3 mm.