Flora of North America species comparison

stoutly trigonous, thickened, 50–300 cm × 5–30 mm, basally indurate, glabrous.

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

V-shaped, with cross ribs, 40–130 cm × 10–15 mm, margins and keel scabrid.

usually basal;

ligules absent;

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

spikes appressed-ascending, narrowly cylindric, (2–)3–45 mm × (4–)7–10 mm;

rays (5–)9–12, 2–22(–30) cm; 2d order rays distinctly flattened, 1–10 cm; 3d order rays flattened, 0.5–3 cm;

rachis 2.5–4 cm;

bracts (6–)9–10, ascending at 45–75°, V- or inversely W-shaped, (5–)15–90 cm × 0.5–20 mm;

rachilla persistent, wings 0.2–0.4 mm wide.

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.

(4–)10–35, appressed-ascending, compressed, linear, 7–12(–15) × 0.6–1.2 mm;

floral scales deciduous, 6–20, marginally clear, laterally brown, medially green, laterally 2–3-ribbed, medially 1-ribbed, oblong-ovate, (3.2–) 3.8–4.3 × 1.2–1.7 mm, apex spreading, acute to obtuse, mucronulate.

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

anthers 0.7–0.9 mm, connective apex bright red, oblong, to 0.1 mm;

styles 0.8–1.3 mm;

stigmas 2–3.3 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, sessile, narrowly ellipsoid, 1.8–2.5 × 0.8–1.3 mm, apex ± acute, not apiculate, surfaces puncticulate.

biconvex, flattened, or trigonous.