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1 Widest leaves 4-8 mm wide; inflorescences more-or-less capitate (occasionally with the lowermost 1 or 2 spikes separated | |
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2 Lateral spikes usually pedunculate; lowermost inflorescence bracts sometimes with sheath; peduncles with prophyll at base. | |
3 Terminal spike gynecandrous, pistillate flowers as many as or more numerous than staminate; lateral spikes short, not much longer than wide; fresh perigynia white-pulverulent | |
3 Terminal spike usually staminate or, sometimes, gynecandrous, staminate flowers then more numerous than pistillate; lateral spikes oblong, distinctly longer than wide; fresh perigynia green or slightly glaucous. | |
7 Terminal spike staminate, androgynous, or gynecandrous (if gynecandrous, the staminate flowers more numerous than the pistillate); lateral spikes at least 2× as long as wide | |
7 Terminal spike staminate or gynecandrous (if gynecandrous, the pistillate flowers more numerous than the staminate); lateral spikes not much longer than wide | |
6 Perigynia smooth. | |
12 Margins of perigynia rounded, or with flat portion < 0.1 mm wide. | |
14 Margins of perigynia rounded or with a very narrow rounded edge; achenes nearly filling the perigynium bodies | |
14 Margins of perigynia sharply edged or narrowly winged; achenes distinctly smaller than the perigynium bodies. | |
8 Terminal spike androgynous (rarely entirely staminate or entirely pistillate); lateral spikes androgynous, staminate, or pistillate. | |
10 Perigynia mostly < 2× as long as wide, widest near middle. | |
11 Inflorescence usually branched, at least at the base, usually with > 15 spikes; pistillate scales usually yellow or brown, sometimes with hyaline margins, 3-veined | |
11 Inflorescence unbranched or with 1 or 2 short branches at the base, with < 15 spikes; pistillate scales greenish hyaline, 1-veined | |
18 Fronts of leaf sheaths dotted red, brown, or yellow. | |
19 Perigynia widest near the middle; culms usually < 1 mm wide. | |
20 Plants loosely cespitose, sometimes with long rhizomes; pistillate scales (at least the upper) obtuse | |
18 Fronts of leaf sheaths not dotted red, brown, or yellow. | |
22 Upper leaves of culms with front of sheaths green-veined, not differentiated from the rest of the sheath | |
23 Perigynia with flat, winglike margins > 0.1 mm wide; plants long-rhizomatous, not cespitose, sometimes forming large colonies | |
23 Perigynia without a flat margin, or with a flat margin < 0.1 mm wide; plants short-rhizomatous or inconspicuously rhizomatous, cespitose or not, sometimes forming large colonies. | |
24 Plants colonial from long rhizomes or stoloniferous (proliferating from last year’s decumbent sterile culms) | |
25 Plants rhizomatous from creeping rhizomes 1.8-3.5 mm in diameter | |
24 Plants cespitose. | |
26 Spikes not consistently androgynous, the terminal either entirely staminate or pistillate, the lateral spikes irregularly pistillate, or staminate, or mixed | |