Flora of North America species comparison

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

and leaves with Kranz (chlorocyperoid) anatomy.

usually basal;

ligules absent;

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

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.

spikes;

rachilla persistent, wingless or nearly so.

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

borne in loosely spicate to ± digitate clusters;

floral scales deciduous, 2-keeled or folded.

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.

stamens (1–)2–3;

pistils 2;

stigmas 2.

biconvex, flattened, or trigonous.

biconvex or ± cylindric, laterally compressed, edge borne toward rachilla.