Flora of North America species comparison

terete or obtusely trigonous, 30–80 cm × 1–5 mm, soft to hard, not septate-nodulose, internally spongy, transverse septa incomplete;

plants never forming filiform, flaccid culms.

terete, often with 10–18 blunt ridges when dry, 10–50 cm × 0.3–2 mm, firm to rigid, spongy.

distal leaf sheaths persistent, membranous, apex acute to acuminate, often prolonged into a slender awn to 4 mm.

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.

not proliferous, 14–54 × 3–5.6 mm;

rachilla joints without winglike remnants of floral scales;

proximal scale empty, amplexicaulous, 2.5–4.9 mm;

floral scales 40–180, 2–3 per mm of rachilla, stramineous to pale brown, flanks sometimes minutely dotted reddish, usually with pale to dark brown, reddish, or purplish submarginal band, obovate to suborbicular, widest in middle, 3.4–4.5(–6) × 3–4.8 mm, cartilaginous, membranous toward margins, margins broadly translucent, membranous, apex rounded.

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 6–7, medium brown to pale brown or reddish, slender, proximally slightly flattened, subequal to unequal, mostly exceeding achene, 2–3.4 mm, smooth or sometimes finely retrorsely spinulose;

anthers reddish brown, 1.7–2.5 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.

brown, biconvex, obpyriform, 2.2–2.8 × 1.3–1.9 mm, markedly sculptured at 10–15X, each face with (17–)20–24 rows of isodiametric to slightly transversely elongated cells, apex narrowed to a stout, often pale, spongy region 0.8–1.1 mm wide at base, 1/2–3/4 of achene width.

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.

dark brown, lamelliform to pyramidal, 0.1–0.5 × 0.2–0.5 mm.

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