Flora of North America species comparison

often ascending, often spotted or streaked red-brown, cross section quadrangular or broadly elliptic, often sulcate, 1.5–8(–25) cm × 0.1–0.3 mm, soft.

distal leaf sheaths persistent or fugaceous, closely sheathing, not conspicuously wrinkled, colorless or pale brown, sometimes spotted red-brown, delicately membranous, apex narrowly acute.

2–4 × 1–2 mm, sometimes absent in deeper water;

proximal scale 1/2 or more of spikelet length;

floral scales 6–10 per spikelet, 1.4–2.7 mm, commonly entirely stramineous, apex rounded to subacute.

basal spikelets absent; never proliferous, ovoid or ellipsoid, laterally compressed or terete, 1.5–3.7 × 0.8–3 mm, apex acute;

proximal scale empty, persistent, amplexicaulous, similar to floral scales;

subproximal scale with a flower;

floral scales distichous (spirodistichous), 8–22, 6–10 per mm of rachilla, colorless or pale brown, mottled red-brown to purple, ovate, (1–)2 × 1 mm, membranous, midribs green and red-brown, prominent, apex rounded to obtuse.

perianth bristles 6, stramineous, fairly stout to slender, usually equaling achene to slightly exceeding tubercle, sometimes unequal and some 1/2 of achene, very rarely rudimentary, minutely retrorsely spinulose;

anthers 0.7–1.2 mm.

perianth bristles present or absent, (1–)4, colorless to white, vestigial to shorter than achene, 0–0.55 mm;

spinules not evident at 45X;

stamens (1–)3;

anthers 0.35–0.45 mm;

styles 2-fid (or 3-fid).

stramineous, sometimes pale brown, obovoid to obpyriform, thickly trigonous, angles distinct, faces concave to plane, rarely convex, 0.9–1.2 × 0.55–0.75 mm, apex tapered, smooth or faintly rough at 30X.

whitish to pale brown, obovoid, biconvex, rarely trigonous, angles prominent, 0.5–0.8 × 0.4–0.6 mm, apex slightly constricted proximal to tubercle, smooth.

terminating rhizomes usually markedly J- or horseshoe-shaped, body (apart from apical bud) oblong, 2–2.5(–5) × 0.5–1 mm;

tubers among culm bases straight, narrowly fusiform, 4–5 mm.

0.1–0.2 × 0.15 mm.

sessile, green or red-brown, pyramidal, birettaform or umbonate, 0.15–0.25 × 0.3–0.4 mm.

= 10 (Europe).