Flora of North America species comparison

2–40 cm × 0.5–1.5(–2) mm.

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.

apex of distal leaf sheath obtuse to acute, tooth to 0.3 mm.

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

lanceoloid to subcylindric or ovoid, 5–10(–20) × 2–3(–4) mm, apex acute (to rounded);

proximal scale empty, encircling ca. 2/3 of culm;

floral scales 25–100(–200), 8–12 per mm of rachilla, orangebrown to stramineous, 2(–2.5) × 1–1.3 mm, midribs mostly keeled, ovate, apex narrowly rounded to subacute.

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 present or often absent, 5–8, brown, stout, rudimentary to slightly exceeding tubercle;

stamens (2–)3;

anthers brown to yellow, 0.3–0.7(–1) mm;

styles 2–3-fid.

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.

0.9–1.1(–1.5) × 0.7–1.1 mm.

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.

depressed, subdeltoid, 0.1–0.3(–0.4) × 0.6–0.9(–1) mm, 1/10–2/5 as high as wide, 1/4 or less as high as achene, 9/10 as wide as achene, very rarely 2/5 as high as achene (in E. engelmannii var. robusta).

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

= 10.