Carex sect. Lupulinae
Carices North. U.S., 562. 1847.
Plants cespitose or not, rarely colonial, short to long rhizomatous. Culms purplish or reddish, rarely brown at base. Leaves: basal sheaths not fibrous; sheath fronts membranous; sheaths and larger leaves distinctly septate-nodulose; blades V-shaped in cross-section when young, glabrous. Inflorescences racemose, with 2–6 (–9) spikes; proximal bracts leaflike, sheathless or sheath less than 4 mm, shorter or longer than diam. of stem; lateral spikes pistillate or the distal 1 (–5) staminate or androgynous, globose, ovoid, or cylindric, pedunculate, prophyllate; terminal spike staminate. Proximal pistillate scales with apex obtuse to acuminate, often awned. Perigynia ascending to spreading, distinctly 15–20-veined, sometimes stipitate, inflated, ovate, ± round in cross-section, 10–20 mm, base cuneate to rounded, apex tapering or abruptly beaked, glabrous or sparsely hairy; beak conspicuously bidentate, teeth not more than 1 mm. Stigmas 3. Achenes trigonous, smaller than bodies of perigynia; style persistent.
e North America
Species 6 (6 in the flora).
Members of Carex sect. Lupulinae have the largest perygynia of all Carex. Mature achenes are critical for identification of some species.
|1||Sheath of the distal nonbracteal leaf 0–1.5(–2.5) cm; beak of perigynium 1.5–4.2 mm; achenes elliptic or obovate; spikes globose to short-ovoid.||> 2|
|1||Sheath of the distal nonbracteal leaf usually 1.7 cm or longer; beak of perigynium 4.5–10 mm; achenes rhombic or nearly triangular; spikes ovoid to cylindric.||> 3|
|2||Perigynia radiating out in all directions to form globular spike, rhombic-ovoid, base cuneate, 8–35 per spike.||Carex grayi|
|2||Perigynia ascending to spreading or, sometimes, the basalmost reflexed to form an ovoid to obovoid spike, lanceoloid to ovoid, base convex, 1–12(–20) per spike.||Carex intumescens|
|3||Achenes distinctly wider than long, widest beyond midle; perigynia stiffly spreading at right angles to rachis.||Carex gigantea|
|3||Achenes as wide as long as or longer, widest near middle; perigynia ascending.||> 4|
|4||Angles of achenes pointed, often knobbed, with hard, nipplelike points; achenes (2.2–)2.4–3.4 mm wide, often nearly as wide as long.||Carex lupuliformis|
|4||Angles of achenes smoothly curved, not pointed or knobbed; achenes 1.7–2.6(–2.8) mm wide, longer than wide.||> 5|
|5||Staminate peduncle 0.5–6(–7) cm, shorter than to exceeding distal pistillate spike by no more than 2 cm; plants loosely cespitose or not, short-rhizomatous.||Carex lupulina|
|5||Staminate peduncle (3–)6–18 cm, usually exceeding distal pistillate spike by 2–12 cm; plants loosely colonial, long-rhizomatous.||Carex louisianica|