Flora of the Southeastern United States
2022 Edition

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Key to Carex, [26d] Section 4.0 Phaestoglochin: section Phaestoglochin (Bracteosae)

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1 Sheaths loose, membranaceous, and fragile on the ventral side, septate-nodulose and usually mottled or striped with green and white on the dorsal side; widest leaves 3-10 mm.
..2 Bodies of pistillate scales 1.5-2.5 mm long, 1.1-1.8 mm wide, mostly < ½ as long as the perigynia, apex obtuse to acuminate to shortly awned.
....3 Basal internodes of the inflorescence usually < 1 cm long, and usually < 2× as long as the spikes; bodies of perigynia with wing < 0.1 mm wide
....3 Basal internodes of the inflorescence usually >2 cm long, at least 2× as long as the spikes; bodies of perigynia with wing 0.1-0.2 mm wide
..2 Bodies of pistillate scales 2.2-4.4 mm long, 1.2-2.4 mm wide, mostly > ½ as long as the perigynia, apex acuminate to awned.
......4 Fronts of leaf sheaths yellow or brownish, thick, firm, the back often white-spotted
......4 Fronts of leaf sheaths white, hyaline, fragile, the backs not white-spotted.
1 Sheaths tight on the ventral side, neither septate-nodulose nor mottled with green and white on the dorsal side.
........5 Perigynia not conspicuously corky-thickened at base.
..........6 Inflorescence ovoid in outline, the spikes densely aggregated, nearly indistinguishable except by the projecting setaceous bracts which subtend each spike.
............7 Perigynia 1.3-1.7× as long as wide, widest near the broadly rounded, truncate, or even subcordate base
............7 Perigynia 1.6-2.5× as long as wide, widest just below the middle, the base broadly cuneate to rounded.
..............8 Pistillate scales (excluding the awns) shorter than the perigynium body; culms not greatly exceeding the leaves
..............8 Pistillate scales (excluding the awns) as long as or exceeding the perigynium body; culms much exceeding the leaves
..........6 Inflorescence spicate-racemose, the individual spikes readily distinguishable (often separated by an exposed internode of the axis).
................9 Pistillate scales brown or reddish-purple; [alien, sparsely naturalized in our area].
................9 Pistillate scales green, hyaline, or pale tan; [native in our area (except C. austrina and C. muricata ssp. lamprocarpa), common and widespread in our area].
..................10 Spikes with 5-10 perigynia; pistillate scales brown with green-veined center
..................10 Spikes with 8-20 perigynia; pistillate scales scarious-white (rarely brown) with green-veined center.
....................11 Perigynia ascending, nerveless on the ventral surface; scales awned, the awns 1.5-4 mm long; lowest inflorescence bract elongate, the free portion 1-5 cm long
....................11 Perigynia spreading, either nerved or nerveless on the upper (ventral) surface; scales acuminate or with an awn to 1.5 (-2.0) mm long; lowest inflorescence bract short, delicate, the free portion 0.5-2 cm long.
......................12 Perigynia 3.0-3.5 mm long, nerveless on the upper (ventral) face
......................12 Perigynia 3.5-4.0 mm long, nerved on both faces
........5 Perigynia corky-thickened in the lower 1/3 to 1/2 at maturity.
........................13 Basal scales and sheaths purplish-tinted; perigynia ascending to spreading at maturity; [rare alien]
........................13 Basal scales and sheaths light tan or brown; perigynia spreading or reflexed at maturity; [native species].
..........................14 Leaves 2.2-4.6 mm wide; perigynia 3.3-5.6 mm long, beaks (1-) 1.4-1.8 mm long
..........................14 Leaves 0.5-3 mm wide; perigynia not > than 4.0 long, beaks 0.3-1.2 mm long.
............................15 Beak of perigynium serrulate; pistillate scales acuminate-awned; perigynia mostly > 20 per spike
............................15 Beak of perigynium smooth or serrulate; perigynia (2-) 3-12 (-20) per spike.
..............................16 Beak of perigynium smooth; pistillate scales acuminate, early deciduous.
................................17 Average perigynium width ≥ 1.3 mm; average spongy portion of the perigynium ≥ 1.1 mm long; perigynium base distinctly nerved, bulging on the ventral surface, making the perigynium biconvex in cross-section; perigynium 2-2.5× as long as wide; perigynium gradually narrowed to a short beak; leaves 1-3 mm wide
................................17 Average perigynium width < 1.3 mm; average spongy portion of the perigynium < 1.1 mm long; perigynium base nerveless, flattened on the ventral surface, making the perigynium planoconvex in cross-section; perigynium ca. 3× as long as wide; perigynium narrowed to a conspicuous beak; leaves 0.75-1.5 mm wide
..............................16 Beak of perigynium serrulate; pistillate scales obtuse, persistent.
..................................18 Plants with creeping rhizomes, the culms arising scattered along the rhizome; perigynia 4-5× as long as wide
..................................18 Plants densely cespitose, the culms arising from the center of clump; perigynia 2-3× as long as wide.
....................................19 Widest leaves 0.9-1.7 mm wide; base of fertile culm 0.7-1.4 mm wide.
......................................20 Base of perigynium cuneate to rounded; distance from base of perigynium to base of achene 0.1-0.5 mm; [primarily of the Mountains in our area]
......................................20 Base of perigynium rounded to truncate; distance from base of perigynium to base of achene 0.5-0.9 mm; [widespread in our area]
....................................19 Widest leaves 1.7-3.0 mm wide; base of fertile culm 1.4-2.2 mm wide.
........................................21 Stigmas 0.03-0.06 mm thick, straight to slightly twisted; widest leaves < 2.0 mm wide; perigynia 3-7 (-8) per spike
........................................21 Stigmas 0.07-0.10 mm thick, mostly coiled; widest leaves > 1.7 mm wide; perigynia (6-) 7-14 (-20) per spike