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Habit Plants cespitose or not, short to long rhizomatous.
Culms

brown or purple at base.

Leaves

basal sheaths not fibrous;

sheath fronts membranous;

blades M-shaped in cross section when young, adaxial side of blade with 2 lateral veins more prominent than midvein, widest blades not more than 6 mm, glabrous or sheaths hispidulous.

Inflorescences

racemose, with (1–)3–6 spikes;

proximal nonbasal bracts leaflike, long sheathing;

lateral spikes pistillate or rarely androgynous, sometimes 1–2 basal, pedunculate, prophyllate;

terminal spike staminate.

Perigynia

ascending, yellow-brown to dark brown when mature, distinctly impressed veined, ovoid or obovoid to narrowly elliptic, rounded-trigonous or round in cross section, base tapering or rounded, apex rounded or somewhat tapering, abruptly contracted to beak or beakless, glabrous;

beak straight or excurved, 0–1.3 mm, orifice entire.

Achenes

trigonous, smaller than bodies of perigynia;

style deciduous.

Proximal

pistillate scales with apex rough-awned, awn to 8.3 mm.

Stigmas

3.

Carex sect. Griseae

Distribution
North America; Mexico
Discussion

Species 21 (20 in the flora).

The monophyly of Carex sect. Griseae is supported by the presence of numerous veins (sclerenchyma traces) that are impressed in both fresh and dry perigynia (R. F. C. Naczi 1992, 1997). Carex sect. Careyanae also has veins impressed in the perigynia when fresh, supporting the view that it is a sister group to sect. Griseae. However, Carex sect. Careyanae has dry perigynia with raised veins and perigynia that are acutely angled, in contrast to the obtusely angled or nonangled perigynia in Carex sect. Griseae.

Mature, complete, and ample specimens are necessary for reliable identification of most of the species of Carex sect. Griseae. Specimens should include rhizomes, vegetative shoots, and shoots of the previous season (sometimes dead by the time of fruiting); these features are absent from many herbarium specimens. Depauperate specimens are often difficult or impossible to identify, particularly since many of the species overlap in the ranges of measurements for diagnostic characters. When determining the presence or absence of purple-red coloration of shoot bases and the height of such coloration, shoot bases should be examined in bright light with magnification.

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

Key
1. Culm bases brown.
→ 2
1. Culm bases purple-red.
→ 10
2. Leaf sheaths scabrous to hispidulous; perigynium beak (0.5–)0.6–1.3 mm.
→ 3
2. Leaf sheaths glabrous; perigynium beak 0–0.5(–0.7) mm.
→ 4
3. Leaf blades green, glabrous abaxially or sparsely hispidulous; perigynia (4.5–)4.6– 5.6(–6.2) × 1.9–2.2(–2.3) mm; longest terminal spikes 14–34(–42) mm.
C. hitchcockiana
3. Leaf blades, especially of overwintered leaves, glaucescent, papillose abaxially; perigynia (3.7–)4–4.7(–5.1) × 1.5–1.7(–1.8) mm; longest terminal spikes (25–)30– 46 mm.
C. brysonii
4. Leaf blades glaucous; pistillate scales awnless or awn not more than 1(–1.9) mm.
→ 5
4. Leaf blades deep or light green; pistillate scales usually with awns 1.2–3.7(–6) mm, rarely awnless.
→ 7
5. Perigynia (4–)4.2–5.5(–6) mm; achene bodies 0.37–0.5 times as long as perigynia; pistillate spikes (5–)5.7–8(–9.6) mm wide; achene beak straight to bent less than 30° from vertical.
C. flaccosperma
5. Perigynia 3.2–4.5(–4.7) mm; achene bodies 0.5–0.63(–0.67) times as long as perigynia; pistillate spikes (3.3–)4.2–6.1(–7.3) mm wide; achene beak usually bent 30–90° from vertical.
→ 6
6. Perigynia 3.2–4(–4.1) mm, (1.5–)1.8–2.3(–2.5) times as long as wide; longest pistillate spikes with (14–)19–45(–65) perigynia, ratio of spike length (in mm) to flower number = (0.56–)0.67–1.1(–1.3).
C. glaucodea
6. Perigynia (3.7–)3.9–4.5(–4.7) mm, (1.9–)2.1–2.6(–2.8) times as long as wide; longest pistillate spikes with 11–25(–28) perigynia, ratio of spike length (in mm) to flower number = (0.97–)1–1.3(–1.6).
C. pigra
7. Peduncles of lateral spikes scaberulous; perigynia (6–)18–37(–86) per spike, (2.5–)2.8–3.6(–4.3) mm, 17–25-veined.
C. conoidea
7. Peduncles of lateral spikes glabrous or scaberulous; perigynia (3–)5–16(–19) per spike, (3.6–)4–5(–5.5) mm, 40–65-veined.
→ 8
8. Widest leaf blades 2.6–4 mm wide; ligules of proximal bracts 0.4–1.8 (–3.6) mm; perigynium apex bent; achene beaks bent.
C. impressinervia
8. Widest leaf blades (3.7–)4.2–8.2(–9.1) mm wide; ligules of proximal bracts (1.8–)4–10.7(–12.9) mm; perigynium apex straight; achene beaks straight.
→ 9
9. Perigynia orbicular to suborbicular in cross section, 1.8–2.3(–2.6) times as long as wide, (1.8–)2–2.6 mm wide; achenes 1.7–2.1(–2.2) mm wide, stipes (0.2–)0.3–0.4(–0.5) mm.
C. grisea
9. Perigynia obtusely triangular in cross section, (2.2–)2.5–3.1 times as long as wide, 1.5–1.9(–2.2) mm wide; achenes (1.3–)1.5–1.7(–1.8) mm wide, stipes (0.3–)0.4–0.6 mm.
C. amphibola
10. Plants not cespitose; rhizome internodes 2–3.4 mm thick; terminal spikes (2.8–)3.3– 4.5(–5.4) mm wide, usually much exceeding distal bract.
C. ouachitana
10. Plants cespitose; rhizome internodes 1.2–2.2 mm thick; terminal spikes (0.9–)1.3–2.9(–3.1) mm wide, usually much exceeded by distal bract.
→ 11
11. Perigynia spirally imbricate; proximal bracts with sheaths loose; ligules (0.9–)2–12.9 mm.
→ 12
11. Perigynia distichously imbricate; proximal bracts with sheaths tight; ligules 4–4.9(–9.6) mm (to 2.2 mm in C. bulbostylis).
→ 15
12. Culm bases with purple-red to (3.4–)4–7.3 cm high; widest leaf blades 2.4–4 (–5.3) mm wide; achene stipes 0.6–0.8(–0.9) mm.
C. godfreyi
12. Culm bases with purple-red to 0.3–2.4(–7.3) cm high; widest leaf blades 3.3–8(–9.1) mm wide; achene stipes (0.2–)0.3–0.6 mm.
→ 13
13. Perigynia (1.8–)2–2.6 mm wide, orbicular to suborbicular in cross section; achene bodies (2.6–)3.1–3.5(–3.7) mm, stipes (0.2–)0.3–0.4(–0.5) mm, bodies 4.8–9.7(–12) times as long as stipes.
C. grisea
13. Perigynia 1.5–2.3(–2.4) mm wide, obtusely triangular in cross section; achene bodies 1.8–2.3(–2.4) mm, stipes (0.3–)0.4–0.6 mm, bodies 3.2–5.8(–7.3) times as long as stipes.
→ 14
14. Perigynia 4.2–5(–5.2) ´ 1.5–1.9(–2.2) mm, (2.2–)2.5–3.1 times as long as wide; achene bodies broadly obovoid to oblong-obovoid, widest at 0.55–0.67(–0.7) of body length.
C. amphibola
14. Perigynia (3.6–)3.9–4.5(–4.7) × (1.7–)1.8–2.3(–2.4) mm, 1.8–2.3(–2.5) times as long as wide; achene bodies broadly obdeltoid-obovoid, widest at (0.6–)0.65–0.8 of body length.
C. corrugata
15. Perigynia much inflated, orbicular or suborbicular in cross section, (1.8–)2– 2.5(–2.8) mm wide, 1.6–2(–2.1) times as long as wide.
C. bulbostylis
15. Perigynia tightly enveloping achene or slightly inflated, obtusely triangular in cross section, 1.4–2.1(–2.3) mm wide, (1.7–)2.1–3.3 times as long as wide.
→ 16
16. Plants loosely cespitose; longer rhizomes internodes 7–58 mm.
C. paeninsulae
16. Plants densely cespitose; longer rhizomes internodes 0.2–6(–8) mm.
→ 17
17. Proximal bracts with bases of blades white between veins (most easily seen on abaxial surface).
C. acidicola
17. Proximal bracts with bases of blades uniformly green.
→ 18
18. Perigynia (1.7–)2.1–2.6 times as long as wide, apex usually abruptly contracted; beak (0.3–)0.5–1.2 mm; longest lateral spike with 2–8(–10) perigyina (including undeveloped or aborted ones).
→ 19
18. Perigynia (2.4–)2.5–3.3 times as long as wide, apex gradually tapering; beakless or beak 0.1–0.4 mm; longest lateral spike with (5–)7–14 perigynia (including undeveloped or aborted ones).
→ 21
19. Proximalmost spike usually considerably beyond base of culm; longest vegetative shoot 0.88–1.4 times as long as longest culm; proximal bracts with sheath front convex and elongated (0.8–)1.1–4 mm beyond apex.
C. oligocarpa
19. Proximalmost spike usually basal; longest vegetative shoot (0.8–)1.4–4.4 times as tall as culms; proximal bracts with sheath front apices concave or truncate.
→ 20
20. Culm bases with purple-red extending 2.7–5.2(–5.6) cm; bodies of pistillate scales (2.2–)2.5–3 mm; achene beaks (0.1–)0.2–0.3 mm.
C. calcifugens
20. Culm bases with purple-red extending (3.7–)4.7–11.7 cm; bodies of pistillate scales 1.5–2.1(–2.5) mm; achene beaks 0.05–0.1(–0.15) mm.
C. edwardsiana
21. Perigynia (1.9–)2–2.3 times as long as achene bodies; achene beaks (0.3–)0.4–0.7 mm.
C. planispicata
21. Perigynia 1.7–2 times as long as achene bodies; achene beaks 0.1–0.3(–0.4) mm.
→ 22
22. Longest (per plant) peduncle of terminal spike (2.2–)5.1–8.9(–10.4) cm; 2 distalmost lateral spikes usually widely separate or occassionally overlapping; longest vegetative shoot 0.5–1.3 times as tall as culm.
C. thornei
22. Longest (per plant) peduncle of terminal spike 0.9–3.2(–6.8) cm; 2 distalmost lateral spikes usually overlapping; longest vegetative shoot 1.4–2.2 times as tall as longest culm.
C. paeninsulae
Source FNA vol. 23. Authors: Robert F. C. Naczi, Charles T. Bryson.
Parent taxa Cyperaceae > Carex
Subordinate taxa
C. acidicola, C. amphibola, C. brysonii, C. bulbostylis, C. calcifugens, C. conoidea, C. corrugata, C. edwardsiana, C. flaccosperma, C. glaucodea, C. godfreyi, C. grisea, C. hitchcockiana, C. impressinervia, C. oligocarpa, C. ouachitana, C. paeninsulae, C. pigra, C. planispicata, C. thornei
Synonyms C. unranked Griseae, C. section Oligocarpae
Name authority (L. H. Bailey) Kükenthal: in H. G. A. Engler, Pflanzenr. 20[IV,38]: 516. (1909)
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