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..2 Spikelets arranged in subglobose, umbel-like clusters; achene margins crimped; plants not rhizomatous; [section Longirostres]
..2 Spikelets arranged in tightly globose clusters; achene margins not crimped; plants rhizomatous; [section Polycephalae]
....3 Longest bristles shorter than the achene
......4 Plants cespitose; primary clusters with 10-50 (rarely 7 or fewer) densely clustered spikelets; achene (4.5-) 5-6 mm long
........5 Bristles 2-8 mm long, the central bristle longest on one face, shortest or absent on the other
........5 Bristles 7-12 mm long, essentially of equal length