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 loose to dense, ovoid to cylindric;

rachilla falling early or persistent, wingless or winged.

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

if rachilla articulate at base, spikelets borne in spikes on conspicuous rachis, falling as achenes mature, if rachilla continuous at base, persistent after achenes mature;

floral scales persistent or deciduous;

stamens 3 (1, less frequently 2 in C. squarrosus and C. granitophilus).

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.

stigmas 3.

biconvex, flattened, or trigonous.

trigonous, sometimes dorsiventrally flattened.