Flora of North America species comparison

100–200 cm × 5–15 mm.

to 150 cm × 5–10 mm.

sheaths reaching to middle of culm or higher, fronts convex (to concave) and papery at mouth, veins reaching apex, very rarely diverging leaving triangular, veinless, membranous area;

widest blade 7–22 mm wide.

sheaths reaching beyond or to middle of culm, fronts convex, papery at mouth, veins reaching apex;

widest blade 6–13 mm wide.

subumbellate, with all or most spikelets solitary or in clusters of 2–3(–8) on 4–12 rays, rays not exceeding 10 cm;

involucral bracts that surpass inflorescences 3–6, widest bract 4–15 mm wide.

subumbellate, all or most spikelets solitary or in clusters of 2–7 on 3–11 rays, rays not exceeding 8 cm;

involucral bracts that surpass inflorescences 2–4, widest bract 2–8 mm wide.

10–40, ovoid to lanceoloid, 10–25 × 6–10 mm, base cuneate to rounded;

scales often loosely imbricate, orange-brown to stramineous, usually obscurely lineolate-spotted, 7–10 × 3–4 mm, membranous and translucent, apex 2-fid 0.5–1 mm deep, awns fairly stout, 2–3 × 0.5 mm wide at base.

10–40, ovoid or lanceoloid, 15–40 × 5–6(–8) mm;

scales tightly appressed or in fruit usually loosely imbricate, medium to dark orange-brown, lineolate-spotted at 15X, 7–9 × 3–4 mm, papery, nearly opaque, apex 2-fid 0.5 mm deep, awn fairly stout, 2–3 × (0.3–)0.5 mm at base.

perianth bristles tightly attached to shed achene, pale brown, very stout, equaling achene;

anthers yellow, 4 mm;

styles 3-fid.

perianth bristles weakly attached to shed achene or some to all falling separately, medium brown, 1/2 to equaling length of achene;

anthers dark yellow to orange-yellow, 3.5–5 mm;

styles (2–)3-fid.

grayish or dark brown, often in patches, obovoid to obpyriform, all nearly equilaterally markedly trigonous to slightly compressed, angles equally rounded, 3.8–5.5 × 2–2.9 mm, apex rounded, beak 0.2–0.8 mm, surface rather dull, exocarp cells usually not evident at 20X; in cross section exocarp much thinner than mesocarp and its cells very small, isodiametric;

achene specific gravity greater than water.

dark to medium brown, color variable often on same achene, shape variable, often in same plant, markedly to obscurely trigonous with equally rounded angles to much compressed-trigonous with abaxial angle broadly rounded, or some biconvex in same spikelet, obovoid, 3–4.3 × 2.3–3.1 mm, apex rounded to nearly truncate, beak 0.1–0.5 mm, surface glossy or glossy with dull patches, entirely clearly cellular at 20X or faintly cellular to noncellular at 30X, often in patches; in cross section exocarp 1/3–2/3 of mesocarp thickness and its cells variably enlarged, 1.5–3 times deeper than wide;

achene specific gravity greater to less than water.

= 94.