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Dewey sedge, Dewey's sedge

Habit Plants densely to loosely cespitose, short to long rhizomatous.
Culms

brown at base.

Leaves

basal sheaths fibrous;

sheath fronts membranous;

blades flat or V-shaped in cross section when young, glabrous.

Inflorescences

racemose with (2–)3–9 spikes;

proximal bracts filiform or leaflike, sheathless;

lateral spikes gynecandrous or pistillate, rarely staminate or androgynous, sessile, without prophylls;

terminal spike usually gynecandrous.

Perigynia

appressed-erect to spreading, occasionally recurved, veined or veinless on both faces, sessile, ovate to narrowly lanceolate, plano-convex, base cuneate to rounded, with spongy tissue, margins acutely angled, serrulate or entire distally, apex tapering or abruptly beaked, glabrous;

beak 0.4–2.5(–2.8) mm, with abaxial suture usually nearly closed, margins entire or serrulate, apex entire to shortly bidentate.

Achenes

brown, sessile, biconvex or plano-convex, almost as large as bodies of perigynia, apex rounded;

style deciduous, enlarged at base.

Longest

inflorescences 35–56 mm;

longest proximal internodes (11–)13–34 mm;

longest proximal bracts 15–49 mm.

Proximal

pistillate scales whitish to castaneous, hyaline margins and green, 1-veined center, apex acute or short-awned.

Stigmas

2.

2n

= 54.

Carex deweyana var. deweyana

Carex sect. Deweyanae

Phenology Fruiting spring–summer.
Habitat Wet-mesic to dry-mesic forests, forest edges
Elevation 10–2800 m (0–9200 ft)
Distribution
from FNA
AK; CO; CT; IA; IL; MA; ME; MI; MN; MT; ND; NH; NJ; NM; NY; OH; PA; SD; VT; WA; WI; WY; AB; BC; MB; NB; NL; NS; NT; ON; PE; QC; SK; YT
[BONAP county map]
North America; e Asia
Discussion

Species 8 (6 in the flora).

Species of Carex sect. Deweyanae, particularly C. bolanderi, C. deweyana, and C. leptopoda, can be difficult to identify because of their great morphologic variability and overlapping ranges of measurements of diagnostic characters. For correct identifications, specimens must bear mature perigynia, be complete, and be ample. Perigynia from the middle portions of spikes should be examined because they are the most representative. Perigynium beak length reported here is the distance from the achene summit (as viewed through the perigynium) to the perigynium apex. Culm widths are taken from the middle of the culm.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Longest (per plant) proximal spike 5.5–9.8 mm; perigynium beak 0.4–1.1(–1.3) mm; widest leaf blade 1.3–2(–2.3) mm wide.
C. laeviculmis
1. Longest (per plant) proximal spike 8.7–27 mm; perigynium beak 0.9–2.8 mm; widest leaf blade 1.3–5.9 mm wide.
→ 2
2. Perigynia (3.3–)4.1–6.7 times as long as wide, (3–)4–8-veined abaxially, veins extending unbroken from perigyium base to base of perigynium beak, achenes 1.9–2.9 times as long as wide; widest leaf blade 1.3–4.4 mm wide.
C. bromoides
2. Perigynia 2.3–3.9(–4.2) times as long as wide, 0–7-veined abaxially, veins extending unbroken from perigyium base to base of perigynium beak, achenes 1.2–1.8 times as long as wide; widest leaf blade (2.2–)2.4–5.9 mm wide.
→ 3
3. Ligule of distal leaf on culm 0.9–2.2 mm; pistillate scale body 2.8–4.2 mm; achenes (1.8–)1.9–2.2 mm; longest infructescence with 2–5 spikes.
C. deweyana
3. Ligule of distal leaf on culm (2.1–)3.1–9.1 mm; pistillate scale body 2.1–3.3(–3.8) mm; achenes 1.4–1.9(–2.2) mm; longest infructescence with (4–)5–9 spikes.
→ 4
4. Perigyinium beak 0.9–1.5(–1.7) mm, 28–38% of perigynium length; pistillate scale body (2.3–)2.7–3.8 mm.
C. leptopoda
4. Perigyinium beak (1.4–)1.6(–2.7) mm, 38–50% of perigynium length; pistillate scale body 2.1–2.9(–3.1) mm.
→ 5
5. Perigynium apex with teeth 0–0.2(–0.4) mm, 0–8% perigynium length (avoid perigynia with teeth lengthened by tearing of sinus between teeth); culm papillose at mid height (20X on young culms).
C. infirminervia
5. Perigynium apex with teeth (0.2–)0.3–1 mm, (6–)9–20% perigynium length (avoid perigynia with teeth lengthened by tearing of sinus between teeth); culm smooth, serrulate, or scabridulous at mid height (20X).
C. bolanderi
Source FNA vol. 23. FNA vol. 23. Author: Robert F. C. Naczi.
Parent taxa Cyperaceae > Carex > sect. Deweyanae > Carex deweyana Cyperaceae > Carex
Sibling taxa
C. deweyana var. collectanea
Subordinate taxa
C. bolanderi, C. bromoides, C. deweyana, C. infirminervia, C. laeviculmis, C. leptopoda
Synonyms C. unranked Deweyanae
Name authority unknown (Tuckerman ex Mackenzie) Mackenzie: in N. L. Britton et al., N. Amer. Fl. 18: 114. (1931)
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