Flora of North America species comparison

solitary or close together, trigonous, 5–40(–95) cm, glabrous.

solitary or not, trigonous or round, glabrous or scabridulous with extrorse or antrorse (rarely retrorse) prickles.

(2–)3–7, broadly V-shaped, 3–20(–30) cm × 1.5–3 mm.

usually basal;

ligules absent;

blades keeled abaxially, flat, V-, or inversely W-shaped in cross section.

spikes loosely to densely ovoid to hemispheric, 7–16 mm diam.;

rachis 1–2 mm, or absent;

rays 1–2, 3–45 mm;

if rays absent, inflorescence sessile, dense, 6–20 mm diam;

bracts 2–3, horizontal to reflexed downward, broadly V-shaped, 1–15 cm × 1–3 mm.

terminal, rarely pseudolateral, 1st order subumbellate to capitate, 2d order with spicate or digitately arranged spikelets, rarely a solitary spikelet;

spikelets 1–150; 1st order rays unequal (rarely equal) in length, produced singly from the axils of inflorescence bracts;

involucral bracts 1–22, spirally arranged at culm apex, spreading to erect, leaflike.

(3–)5–25(–60), linear to oblong-linear, (3–)5–9 × 1.8–2.3 mm;

floral scales 4–18, closely imbricate, chestnut brown, black, or brown, medially green or greenish brown, laterally ribless, medially 2(–3)-ribbed, distinctly 2-keeled basally, ovate to orbiculate, 1.5–2.1 × 1.4–2.2 mm, apex obtuse.

scales to 76, distichous, each subtending flower, cylindric to compressed, borne spicately or digitately at ends of rays (occasionally proliferous).

stamens 2;

anthers 0.6–0.8 mm, connectives not prolonged;

styles 0.4–0.6 mm;

stigmas 0.7–2.1 mm.

bisexual [rarely unisexual], in axils of distichous floral scales, bases often decurrent onto rachilla as ± hyaline wings;

perianth absent;

stamens 1–3;

styles linear, 2–3-fid, base deciduous or persistent;

stigmas 2–3.

brown, ellipsoid, 1.2–1.4 × 0.6–0.8 mm, network of ridges forming isodiametric or square cells, slightly stipitate, apex apiculate, surfaces minutely punctate.

biconvex, flattened, or trigonous.