Flora of North America species comparison

diffuse, very fine.

stiff or flaccid, usually terete, ribbed.

(5–) 10–20 cm.

basal, polystichous, spreading to ascending;

sheaths open apically, apex fimbriate-ciliate, rarely entire;

ligules absent, lateral tufts of hair at junction of blade and sheath;

blades mostly linear or filiform, coarsely ribbed, usually longer than sheaths, 1 mm wide or less, mostly strongly involute, margins variably scabrid-ciliate.

1/2–2/3 length of culms;

sheaths brownish to stramineous, glabrous or scabrid along ribs;

blades spreading-recurved, filiform, 0.5 mm wide, involute, margins and adaxial ribs hispidulous.

terminal on slender scapes, rarely axillary to culm leaves, simple or compound anthelae or spikelet solitary;

spikelets 1–50+;

involucral bracts (1–)2–8, spreading or erect, leaflike or scalelike.

scapes erect to spreading, wiry, angularly ribbed, 0.6–1 mm thick, hispidulous;

spikelets in dense, terminal, top-shaped to hemispheric involucrate heads, 1–1.5 cm wide;

longer involucral bracts with setaceous blades many times exceeding heads, gradually dilating to scarious-bordered, entire sheaths.

mostly ovoid to lanceoloid or lance-cylindric;

scales 6–50, spirally arranged, rarely nearly distichous, each subtending flower or 1–2 proximal scales empty.

usually greenish or dull brown, oblong to lance-ovoid, 3–5 mm;

fertile scales ovate, keeled, 3–4 mm, abaxially hirtellous, midrib excurrent forming excurved mucro, scabrid.

bisexual;

perianth absent;

stamens 1–3;

styles slender, (2–)3-fid, glabrous, base enlarged, persistent in fruit.

stamens 1;

anthers oblong, 0.5 mm.

trigonous or 3-lobed, rarely biconvex, usually 3-ribbed.

pale or graybrown, broadly trigonousobovoid, rather sharply 3-ribbed, 1 mm, faces flat or somewhat concave, finely transversely rugose;

tubercle a depressed-conic button.

= 30.