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1 Pistillate spikes all from the base of the plant |
1 Pistillate spikes all or in part borne on the elongate, aboveground stem. |
..2 Bracts of the lowermost non-basal spike with well-developed sheath > 4 mm long. |
....3 Beak of perigynium with distinct teeth > 0.6 mm long |
....3 Beak of perigynium entire, notched, or with indistinct teeth < 0.6 mm long. |
......4 Bracts of the lowermost non-basal spike bladeless, or with a blade < 2 mm long. |
........5 Perigynia 2.0-2.9 mm long; leaf blades 0.9-3.3 mm wide |
........5 Perigynia 4-5 mm long; leaf blades 4-8 mm wide |
......4 Bracts of the lowermost non-basal spike with blade > 3 mm long (and often much longer). |
..........6 Achene tip with persistent, enlarged, circular style base |
..........6 Achene tip with at most a short apiculus. |
............ 7 Leaves pubescent or pilose |
............ 7 Leaves usually glabrous, to scabrous on the veins. |
............ ..8 Bases of plants brown |
............ ..8 Bases of plants distinctly red or purple. |
............ ....9 Lowermost pistillate scales awned; leaves somewhat septate-nodulose; plants usually long-rhizomatous and forming large clonal colonies |
............ ....9 Lowermost pistillate scales obtuse to acuminate; leaves not septate-nodulose; plants cespitose, short-rhizomatous |
..2 Bracts of the lowermost non-basal spike sheathless or with sheath < 4 mm long. |
............ ......10 Perigynia > 10 mm long. |
............ ........11 Pistillate spikes globose, about as long as wide; staminate spikes usually 1 |
............ ........11 Pistillate spikes cylindric, much longer than wide; staminate spikes 1-8 |
............ ......10 Perigynia < 10 mm long. |
............ ..........12 Perigynium beak with 2 teeth > 0.6 mm long |
............ ..........12 Perigynium beak entire or with teeth < 0.6 mm long. |
............ ............ 13 Terminal spike gynecandrous or pistillate |
............ ............ ..14 Perigynia papillate |
............ ............ ..14 Perigynia glabrous or pubescent. |
............ ............ ....15 Sheaths and blades both glabrous |
............ ............ ....15 Sheaths and/or blades pubescent |
............ ............ 13 Terminal spike staminate (or rarely androgynous). |
............ ............ ......16 Leaf sheaths (and usually the blades as well) pubescent. |
............ ............ ........17 Pistillate scales sometimes pubescent; pistillate spikes with 40-200 perigynia |
............ ............ ........17 Pistillate scales glabrous; pistillate spikes with < 40 (-50) perigynia. |
............ ............ ..........18 Perigynia usually < 3.2 mm long, the apex rounded and beakless, or abruptly beaked |
............ ............ ..........18 Perigynia > 3.5 mm long, the tip tapering or abruptly beaked. |
............ ............ ............ 19 Longer peduncles of pistillate spikes > 1 cm long; perigynia > 3× as long as wide, tapering gradually to the base |
............ ............ ............ 19 Longer peduncles of pistillate spikes 0-1 cm long; perigynia < 3× as long as wide, abruptly contracted to a short stipe at the base. |
............ ............ ............ ..20 Perigynia distinctly 20-30-veined; beak < 0.5 mm long |
............ ............ ............ ..20 Perigynia veinless except for 2 marginal veins; beak > 0.7 mm long |
............ ............ ......16 Leaf sheaths and blades glabrous to scabrous. |
............ ............ ............ ....21 Achene tip with persistent, enlarged, circular style base |
............ ............ ............ ....21 Achene tip with at most a short apiculus. |
............ ............ ............ ......22 Leaf blades scabrous on the upper surface; beak of perigynium recurved |
............ ............ ............ ......22 Leaf blades glabrous on the upper surface, often with rough margins or tip; beak of perigynium straight. |
............ ............ ............ ........23 Fronts of sheaths of lower leaves ladder-fibrillose; leaves and sheaths septate-nodulose (sometimes obscurely so) |
............ ............ ............ ........23 Fronts of leaf sheaths not ladder-fibrillose, sometimes breaking into longitudinal fibers; leaves and sheaths not septate-nodulose. |
............ ............ ............ ..........24 Perigynia strongly 12-30-veined. |
............ ............ ............ ............ 25 Pistillate scales with 3-7 (-10) veins |
............ ............ ............ ............ 25 Pistillate scales with 1-3 veins. |
............ ............ ............ ............ ..26 Leaf blades, at least toward the tip, M-shaped in cross-section when young, the upper surface usually with 2 marginal veins more prominent than the midvein; staminate spikes 1-4 |
............ ............ ............ ............ ..26 Leaf blades V-shaped in cross-section when young, the upper surface lacking 2 marginal veins more prominent than the midrib; staminate spike 1 |
............ ............ ............ ..........24 Perigynia 0-12-veined. |
............ ............ ............ ............ ....27 Proximal pistillate spike pendulous, perigynia usually > 30 per spike; terminal staminate spikes 1-3; [exotic] |
............ ............ ............ ............ ....27 Proximal pistillate spike erect, perigynia < 25 per spike; terminal staminate spikes 1; [native]. |
............ ............ ............ ............ ......28 Plants with at least some pistillate spikes basal; culms much shorter than the leaves |
............ ............ ............ ............ ......28 Plants with most pistillate spikes on obvious elongated stems; culms shorter than or longer than the leaves. |
............ ............ ............ ............ ........29 Upper leaves with blades > 2 cm long, longer than the sheaths |
............ ............ ............ ............ ........29 Upper leaves bladeless or with blades < 1 cm long and also shorter than the sheaths |