Flora of North America species comparison

erect, not spirally twisted, not contracted near spikelet, when dry usually with several blunt to acute ridges and sulcate, subterete to slightly compressed, to 2 times wider than thick, 5–35 cm × 0.2–0.5(–1.2) mm, soft to hard;

culm tufts often proximally bulbous (if bulbous then tunicated by papery-fibrous scales).

terete, when dry with few to many blunt ridges, 10–70 cm × 0.5–2 mm, soft to firm, internally hollow with complete transverse septa 2–5 mm apart, usually evident externally except in narrowest culms.

distal leaf sheaths stramineous to brown or reddish proximally, green to stramineous or brown distally, membranous to papery, apex often reddish, subtruncate to acute.

distal leaf sheaths persistent, not splitting, proximally dark red, distally green or brown, slightly callose, papery, apex obtuse, tooth present, 0.3–1 mm.

3–8 × 1.5–4 mm;

proximal scale with a flower, seldom empty, 2–5 mm, 1/2 or more as long as spikelet;

floral scales 3–10 per spikelet, 2.5–6 × 1.5–2.5 mm.

ovoid, 6–21 × 3–4 mm, apex acute to obtuse;

proximal scale amplexicaulous, entire;

subproximal scale empty or with flower;

floral scales appressed in fruit, 100–500+, (15–)30–40 per mm of rachilla, medium brown to colorless, midrib regions greenish to colorless, ovate, 1.5–2.5 × 1–1.5 mm, entire, apex rounded to subacute, carinate in distal part of spikelet.

perianth bristles (0–)3–6, often unequal, rudimentary to equaling tubercle, stout to slender, spinules dense to apparently absent;

anthers 1.5–2.7(–3.5) mm.

perianth bristles 6–8, pale brown, medium stout, from less than 1/2 achene length to sometimes slightly exceeding tubercle, retrorsely spinulose;

stamens 1;

anthers dark yellow to brown, 0.6–1 mm;

styles 3-fid or some 2-fid.

stramineous to medium brown or gray-brown, equilaterally trigonous to compressed-trigonous, rarely some biconvex, obpyriform (to obovoid), 1.6–2.3 × 0.7–1.3 mm, beak variable.

falling with scales, dark green or medium brown, obovoid to obpyriform, biconvex or sometimes some compressedtrigonous in same spikelet, lateral angles prominent, abaxial angle absent or evident, not prominent, 0.8–1.1 × 0.7–0.8 mm, neck short or absent, finely cancellate at 10–20X, sometimes finely rugulose, with 15 horizontal ridges in vertical series.

rarely absent, 0.3–0.4 × 0.2–0.3 mm.

brown, pyramidal, mostly depressed, 0.2–0.35 × 0.2–0.4 mm.