Carex debilis

Michaux

Fl. Bor.-Amer. 2: 172. 1803.

Common names: White-edge sedge weak sedge
IllustratedEndemic
Treatment appears in FNA Volume 23. Treatment on page 469. Mentioned on page 462, 468, 470.

Plants densely cespitose. Culms dark maroon at base; flowering-stems 25–100 cm, as long as leaves at maturity or often longer, 0.5–1 mm thick, glabrous but scabrous within inflorescence. Leaves: basal sheaths maroon, bladeless, glabrous or rarely minutely pubescent; others grading from maroon to green on back, pale brown-hyaline or reddish-brown on front, often red dotted, sometimes finely pubescent; blades flat, 2–7 mm wide, glabrous on both surfaces, margins and abaxial midribs often finely scabrous. Inflorescences: peduncles of lateral spikes slender, to 50 mm, usually shorter than spikes or only slightly longer, scabrous; of terminal spike 15–50 mm, finely scabrous; proximal bracts longer, or more often, shorter than inflorescences; sheaths 1–7 cm; blades 1–3.5 mm wide. Lateral spikes 2–5, 1 per node, well separated, erect at anthesis, soon nodding, pistillate with 10–25 perigynia attached 2–9 mm apart, linear, 25–80 × 2–3 mm. Terminal spike staminate or sometimes gynecandrous with a few pistillate flowers distally; 15–50 × 0.6–1.2 mm. Pistillate scales white-hyaline, sometimes tinged with pale-brown or suffused with chestnut, with broad green midrib, finely red dotted, oblong, 2.8–6 mm, much shorter than mature perigynia, apex obtuse, acute or cuspidate, awn to 0.2 mm, glabrous, distal margin ciliate. Perigynia green to olive-green, usually red dotted, prominently 2-ribbed, finely 12–20-veined, loosely enveloping achene, fusiform to lanceovoid, 5–9.5 × 1.1–2.2 mm, membranous, base acute, apex tapering gradually to abruptly contracted beak, glabrous or short-pubescent; beak bidentate 0.7–2 mm, including teeth to 1 mm. Achenes stipitate, 1.9–2.5 × 1–1.5 mm, stipe 0.5–1.5 mm.

Distribution

V23 858-distribution-map.jpg

N.B., N.S., Ont., P.E.I., Que., Ala., Ark., Conn., D.C., Del., Fla., Ga., Ill., Ind., Ky., La., Maine, Mass., Md., Mich., Minn., Miss., Mo., N.C., N.H., N.J., N.Y., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Va., Vt., W.Va., Wis.

Discussion

Varieties 2 (2 in the flora).

Carex debilis is extremely variable and has been variously subdivided into as many as six varieties or three subspecies. Only two weakly differentiated varieties can be maintained: the typical variety with broadly southern distribution and C. debilis var. rudgei, which replaces it in the Northeast, the Midwest, and the eastern mountains. Both varieties appear to hybridize with C. virescens but these hybrids have not been studied to confirm parentage.

Selected References

None.

Key

1 Perigynia fusiform, 5.5–9.5 mm, tapering very gradually to elongate beak; pistillate scales usually with apex blunt to acute, rarely cuspidate, white or very pale hyaline margins. Carex debilis var. debilis
1 Perigynia lance-ellipsoid, 5–6.2 mm, more abruptly narrowed to beak; pistillate scales with apex acute to cuspidate to short-awned, hyaline margins usually suffused or streaked with reddish brown. Carex debilis var. rudgei

"thick" is not a number.

... more about "Carex debilis"
0.19 cm1.9 mm <br />0.0019 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
trigonous +
1mm;1.5mm +
short-pubescent +  and glabrous +
Marcia J. Waterway +
Michaux +
0 cm0 mm <br />0 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
shortened +
pubescent +  and glabrous +
Hymenochlaenae +
1/2 length of body +
bidentate +
0 cm0 mm <br />0 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
m--shaped +
1mm;3.5mm +
glumaceous +  and foliaceous +
2-ranked +  and arranged +
ascending +  and appressed +
scale-like +  and leaflike +
parallel +  and divergent +
terete +, rolled +  and plicate +
White-edge sedge +  and weak sedge +
dark maroon +
round +  and trigonous +
N.B. +, N.S. +, Ont. +, P.E.I. +, Que. +, Ala. +, Ark. +, Conn. +, D.C. +, Del. +, Fla. +, Ga. +, Ill. +, Ind. +, Ky. +, La. +, Maine +, Mass. +, Md. +, Mich. +, Minn. +, Miss. +, Mo. +, N.C. +, N.H. +, N.J. +, N.Y. +, Ohio +, Okla. +, Pa. +, R.I. +, S.C. +, Tenn. +, Tex. +, Va. +, Vt. +, W.Va. +  and Wis. +
hypogynous +  and subtending +
25 cm250 mm <br />0.25 m <br /> (100 cm1,000 mm <br />1 m <br />) +
biconvex +  and trigonous +
apart +  and separated +
2.5 cm25 mm <br />0.025 m <br /> (8 cm80 mm <br />0.08 m <br />) +
nodding +  and erect +
0.2 cm2 mm <br />0.002 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
multi-ranked +, 2-ranked +, 3-ranked +  and alternate +
basal +  and cauline +
entire +  and bidentate +
red dotted +, reddish-brown +, pale brown-hyaline +, maroon +  and green +
0 cm0 mm <br />0 m <br /> (5 cm50 mm <br />0.05 m <br />) +
with (1-)3-6(-30) bristles and/or scales +
red dotted +, green +  and olive-green +
0.5 cm5 mm <br />0.005 m <br /> (0.95 cm9.5 mm <br />0.0095 m <br />) +
ascending +  and erect +
0.2 cm2 mm <br />0.002 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.22 cm2.2 mm <br />0.0022 m <br />) +
2-3(-4)-carpellate +
, +, suffused with maroon or suffused with chestnut-brown +, white +  and hyaline +
3 (?) +  and 1 (?) +
Fl. Bor.-Amer. +
adventitious +
red dotted +, , +, tinged with pale-brown or tinged with suffused with chestnut +  and white-hyaline +
basal +  and proximal +
0.28 cm2.8 mm <br />0.0028 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
cylindric +
1 cm10 mm <br />0.01 m <br /> (7 cm70 mm <br />0.07 m <br />) +
Illustrated +  and Endemic +
1.5 cm15 mm <br />0.015 m <br /> (5 cm50 mm <br />0.05 m <br />) +
1 (?) +  and 3 (?) +
septate +, hollow +  and solid +
compressed +, terete +  and trigonous +
papillate +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (?) +  and 0.15 cm1.5 mm <br />0.0015 m <br /> (?) +
deciduous +
2-3(-4)-fid +
Carex debilis +
Carex sect. Hymenochlaenae +
species +
0.06 cm0.6 mm <br />6.0e-4 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
0 cm0 mm <br />0 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
plant +  and cespitose +
pubescent +  and glabrous +
not septate-nodulose +