Flora of North America species comparison

trigonous, (20–)60–70(–100) cm × 2.4–6.9 mm, scabrid on angles.

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

4–12, flat to V-shaped, with readily visible cross ribs especially on abaxial surface, 20–50 cm × 3–14 mm.

usually basal;

ligules absent;

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

heads digitate to hemispheric, 1–3.5 cm diam.;

rays 6–12, 1–9(–14) cm; 2d order rays often present, (0.5–)1–3 cm; 3d order rays occasionally present, 5–12 mm;

bracts 4–8, horizontal to ascending at 30°, with prominent cross ribs,V-shaped, (1.5–)3–50(–75) cm × 0.5–13 mm; 2d order bracts 3–10 × 1–2 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.

10–40(–50), oblong to linear-lanceoloid, 5–18 × 2–3.2 mm;

floral scales 10–40, pale grayish brown, or greenish, proximally greenish or brownish, oblanceolate, 2-keeled, weakly to distinctly 1-ribbed, proximal half 2-ribbed, (1.3–)1.5–2(–2.4) × 0.9–1.4 mm, apex acute (sometimes mucronulate), apically glabrous, occasionally scabridulous.

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

stamens 1–2;

anthers 0.8–1.4 mm;

styles 0.8–1 mm;

stigmas 0.6–0.8 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, slightly to distinctly stipitate, ellipsoid (2.7–4.1 times as long as wide), (0.9–)1.2–1.5 × 0.3–0.4 mm, apical beak 0.1–0.5 mm, surfaces glabrous.

biconvex, flattened, or trigonous.