Flora of North America species comparison

to 45 cm × 0.2–1 mm.

terete, when dry with to 12 blunt ribs, 20–55 cm × 0.5–1.1 mm, soft to firm, internally mostly hollow with complete transverse septa 2–4 mm apart, evident only on sectioning culm.

distal leaf sheaths persistent, firm, distally tightly sheathing, apex acute.

distal leaf sheaths persistent, not splitting, proximally dark red, distally stramineous or reddish, thinly papery, apex often red to brown, obtuse to subtruncate, slightly callose, tooth present, 0.5–1(–3.7) mm.

orbicular to ovoid, 1–9 × 1–4 mm, apex rounded to acute;

proximal scale without flower, not amplexicaulous;

floral scales to 125, 11–14 per mm of rachilla, tightly appressed, dark red-brown to stramineous, ovate to elliptic, 0.8–3 × 0.6–2(–2.3) mm, membranous to cartilaginous, apex rounded to acute.

lanceoloid, 5–13 × 2–2.5 mm, apex acute to obtuse;

proximal scale amplexicaulous, entire;

subproximal scale empty;

floral scales appressed in fruit, 10–100, 10–12 per mm of rachilla, medium brown to stramineous, midrib regions often greenish, ovate, 1–1.5 × 1 mm, entire, apex rounded to subacute, carinate in distal part of spikelet.

perianth bristles (0–)4–8, typically 7, red-brown, rarely whitish, vestigial to much exceeding tubercle, typically equaling achene, spinules few to dense;

styles 2-fid.

perianth bristles 5–6, pale brown, stout, equaling achene;

stamens 3;

anthers brown, 0.4–0.9 mm;

styles 3-fid or a few 2-fid in the same spikelet.

brown ripening to black, biconvex, orbicular to obpyriform, 0.5–1.1 × 0.3–0.7 mm, apex rarely constricted proximal to tubercle, very finely reticulate at 40X.

falling with scales, green or medium or dark brown, obpyriform, compressed-trigonous or some biconvex in same spikelet, angles prominent, 0.6–0.8 × 0.5–0.6 mm, neck short or absent, smooth or very finely reticulate at 20–30X.

stramineous to whitish, umbonate to subconic, 0.2–0.4 × 0.2–0.5 mm, apex rounded to acute.

brown, depressed-pyramidal, 0.1–0.2 × 0.2–0.3 mm.

= 10.