Flora of North America species comparison

fertile ones lax, reclining, inflorescences lopping over to (or nearly to) ground;

nodes frequently with axillary bulblets.

fertile ones upright or nearly so;

nodes without axillary bulblets.

10–18 per culm;

proximal leaf sheaths green or brownish;

proximal sheaths and blades with septa few, inconspicuous;

blades 16–55 cm × 4–8 mm.

4–7 per culm;

sheaths of proximal leaves green or brownish;

proximal blades and sheaths with septa few to many, conspicuous or inconspicuous;

blades 30–54 cm × 5–9 mm.

terminal;

rays divergent, proximal rays smooth, pedicels and distal rays scabrous, rays often bearing axillary bulblets;

bases of involucral bracts green or brownish, not glutinous.

terminal;

rays ascending or sometimes spreading, scabrous throughout or main branches smooth proximally, rays rarely with axillary bulblets;

bases of involucral bracts black, glutinous.

in open cymes, central spikelet of each cyme sessile, others long-pedicellate, spikelets cylindric to narrowly ovoid, 4–14 × 1–2 mm;

scales light brown to reddish with broad green midribs, broadly ovate or elliptic, 1.2–1.8 mm, apex rounded to obtuse, apiculate, or sometimes short-mucronate, apiculus or mucro (if present) to 0.1 mm.

in open cymes, central spikelet of each cyme sessile, others usually pedicellate, spikelets ovoid or ellipsoid to cylindric, 3.5–10.5 × 2–3(–5) mm;

scales blackish, at least distally, with pale midribs, elliptic or narrowly elliptic to obovate or narrowly obovate, 2–3.1 mm, apex rounded to obtuse or minutely apiculate, apiculus (if present) less than 0.05 mm.

perianth bristles persistent, 6, stout, contorted, equaling or longer than achene, not projecting beyond it, with delicate, round-tipped, retrorse teeth in distal 1/2, enclosed within scales;

styles 3-fid.

perianth bristles persistent, 6, slender, contorted, much longer than achene, smooth, projecting beyond scales, mature inflorescence appearing woolly;

styles 3-fid.

off-white to yellowish brown, elliptic-obovate in outline, strongly trigonous with very strong angles and concave sides, 0.8–1 × 0.6–0.8 mm.

reddish brown, elliptic or obovate in outline, plano-convex or plumply trigonous, 0.7–1 × 0.4–0.5 mm.

= 28.

= 66, 68.