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FNA | Family List | FNA Vol. 23 | Cyperaceae | Carex

26s. CAREX Linnaeus sect. RACEMOSAE G. Don in J. C. Loudon, Hort. Brit. 376. 1830.

David F. Murray

Carex sect. Atratae (Heuffel) H. Christ; Carex sect. Microrhynchae (Drejer) L. H. Bailey

Plants loosely or densely cespitose, sometimes long rhizomatous or stoloniferous; roots brown or black without yellow-brown felty covering. Culms purple or red at base. Leaves: basal sheaths usually fibrous; sheath fronts membranous, mouth entire, proximal leaves, often dotted or tinged red or purple, rarely prominently veined and becoming ladder-fibrillose, glabrous; blades V-shaped in cross section when young, smooth or papillose. Inflorescences racemose, with 1–10 spikes; proximal bracts threadlike or, rarely, scalelike, sheathless, abaxial surface papillose; lateral spikes pistillate, rarely, gynecandrous with few staminate flowers, pedunculate, prophyllate; terminal spike gynecandrous with few perigynia, staminate, or pistillate. Proximal pistillate scales brown or black, not ciliate, apex obtuse to shortly awned. Perigynia erect or ascending, veined or veinless on faces, with 2 distinct marginal veins, sessile, obovoid to suborbicular, rounded or somewhat compressed in cross section, base cuneate to ± rounded, apex tapering or rounded to beak or rarely beakless, smooth or papillose, glabrous; beak entire or shortly bidentate. Stigmas 2–3. Achenes trigonous, smaller than to almost filling bodies of perigynia; style deciduous.

Species ca. 60 (29 species in the flora): dry plains, wetlands, arctic, alpine tundras in North America and Eurasia.


Hermann, F. J. 1968. Notes on Rocky Mountain carices. Rhodora 70: 419–421. Kalela, A. 1944. Systematische und Pflanzengeographische Studien an der Carex Subsektion Alpinae Kalela. Ann. Bot. Soc. Zool.-Bot. Fenn. “Vanamo” 19(3). Murray, D. F. 1969. Taxonomy of Carex sect. Atratae (Cyperaceae) in the southern Rocky Mountains. Brittonia 21: 55–76.

1 Terminal spike staminate (or androgynous in C. adelostoma).   (2)
+ Terminal spike gynecandrous (or wholly pistillate in C. parryana, C. hallii, and C. idahoa).   (10)
2 (1) Lateral spikes always present, all spikes of similar length.   (3)
+ Lateral spikes absent, or mostly much shorter than terminal spike as long as terminal in C. parryana (C. hallii and C. idahoa can have single, terminal, staminate spike) [See also the key to unispicate Carex].   (6)
3 (2) Leaves 3–7 mm wide; perigynia smooth; culms smooth or nearly so.   225 Carex raynoldsii
+ Leaves 1.5–4 mm wide; perigynia papillose; culms scabrous.   (4)
4 (3) Perigynia distinctly beaked, veinless.   211 Carex stylosa
+ Perigynia beakless or minutely beaked.   (5)
5 (4) Perigynia brown, obscurely veined; arctic.   212 Carex holostoma
+ Perigynia pale green, veinless; subarctic.   217 Carex adelostoma
6 (2) Perigynia 3–6.6 × 1.2–3.4 mm; beak veined, 0.5–1 mm.   (7)
+ Perigynia 2–3 × 2–2.5 mm; beak veinless, minute to 0.2 mm.   (8)
7 (6) Perigynia (2–)3–5 × 1.2–2 mm.   226 Carex serratodens
+ Perigynia (4.7–)5–6.6 × 2.2–3.4 mm.   227 Carex aboriginum
8 (6) Pistillate scales dark brown to black, mostly exceeding perigynia.   215 Carex idahoa
+ Pistillate scales light to dark brown, shorter than, equaling, or only barely exceeding perigynia.   (9)
9 (8) Lateral spikes much shorter than terminal spike.   214 Carex hallii
+ Lateral spikes (1 or more) as long as terminal spike.   213 Carex parryana
10 (1) Lateral spikes sessile or short-pendunculate; spikes, at least proximal, sometimes separate and distinct; distal spikes forming dense terminal cluster.   (11)
+ Lateral spikes pedunculate; spikes contiguous or separate; distal spikes not forming a dense terminal cluster.   (18)
11 (10) Achenes nearly filling body of perigynia.   (12)
+ Achenes filling proximal 1/2 or less of perigynia.   (14)
12 (11) Plants with long-creeping rhizomes; perigynia 4–5 mm; beak 0.6–0.8 mm; pistillate scales longer than perigynia; Yukon, Alaska.   209 Carex sabulosa
+ Plants without long-creeping rhizomes; perigynia 2–3.5 mm; beak 0.2–0.4 mm; pistillate scales; North America, Eurasia.   (13)
13 (12) Perigynia green or golden brown, veinless; pistillate scales with hyaline margins, equaling or shorter than perigynia.   205 Carex norvegica
+ Perigynia dark brown to purple-black, often veined proximally; pistillate scales without hyaline margins, 1/2 as long as perigynia.   206 Carex media
14 (11) Perigynia ovate or elliptic.   (15)
+ Perigynia obovate.   (16)
15 (14) Perigynia ovate, abruptly beaked; pistillate scales dark brown to almost black with hyaline margins; beak 0.4–0.5 mm.   223 Carex nova
+ Perigynia elliptic, gradually beaked; pistillate scales blue-black with hyaline margins; beak 0.8–0.1 mm.   224 Carex nelsonii
16 (14) Pistillate scales as wide as perigynia, usually shorter than or equaling perigynia; distal margins of perigynia papillose, frequently serrulate.   223 Carex nova
+ Pistillate scales narrower than perigynia, usually longer than perigynia; distal margins of perigynia smooth, not serrulate.   (17)
17 (16) Perigynia dark brown to purple-black; pistillate scales attenuate and mucronate, more than to 2 times as long as perigynia.   221 Carex helleri
+ Perigynia glossy reddish brown; pistillate scales acute, equaling or barely exceeding perigynia.   222 Carex pelocarpa
18 (10) Proximal lateral spikes spreading or pendent.   (19)
+ Proximal lateral spikes erect, not spreading or pendent.   (24)
19 (18) Perigynia ovate.   (20)
+ Perigynia broadly elliptic or obovate.   (21)
20 (19) Leaves basal and cauline; proximal leaves bladeless, reduced to sheaths; pistillate scales conspicuously shorter than perigynia.   208 Carex mertensii
+ Leaves all basal; proximal leaves with blades; pistillate scales equaling or exceeding perigynia.   202 Carex chalciolepis
21 (19) Perigynia broadly elliptic, papillose.   201 Carex atratiformis
+ Perigynia obovate, smooth.   (22)
22 (21) Pistillate scales as broad as perigynia.   218 Carex bella
+ Pistillate scales narrower than perigynia.   (23)
23 (22) Terminal spike with 1/3–2/3 staminate flowers at base; perigynia light green; pistillate scales with midveins lighter colored than bodies.   219 Carex heteroneura
+ Terminal spike with fewer than 1/4 staminate flowers at base; perigynia brown with light colored margins; pistillate scales with midveins same color as bodies.   220 Carex epapillosa
24 (18) Lateral spikes of varying lengths, mostly shorter than terminal spike (Carex hallii and C. idahoa can have a single, terminal spike).   (25)
+ Lateral spikes of similar length.   (27)
25 (24) Pistillate dark brown to black, scales exceeding perigynia.   215 Carex idahoa
+ Pistillate scales light to dark brown, shorter than, equaling, or barely exceeding perigynia.   (26)
26 (25) Lateral spikes much shorter than terminal spike.   214 Carex hallii
+ Lateral spikes (1 or more) as long as terminal spike.   213 Carex parryana
27 (24) Perigynia ovate, gradually beaked; beak 0.5–1 mm, bidentate, teeth spreading.   (28)
+ Perigynia obovate or broadly elliptic, beakless, minutely beaked, or distinctly, abruptly beaked; beak 0.2–0.5 mm, teeth, when present, not spreading.   (29)
28 (27) Perigynia (2–)3–5 × 1.2–2 mm.   226 Carex serratodens
+ Perigynia (4.7–)5–6.6 × 2.2–3.4 mm.   227 Carex aboriginum
29 (27) Pistillate scales ovate or broadly lanceolate, apex blunt.   (30)
+ Pistillate scales lanceolate, apex acute to conspicuously long-mucronate.   (31)
30 (29) Spikes short-oblong or cylindric, 3–4.5 mm wide; perigynia 2–2.5 mm; beak 0.2–0.25 mm.   207 Carex stevenii
+ Spikes oblong or elongate, 5–6 mm wide; perigynia 2.5–3.5 mm; beak 0.3–0.5 mm.   204 Carex atrosquama
31 (29) Pistillate scales conspicuously long-mucronate.   (32)
+ Pistillate scales acute or short-mucronate.   (33)
32 (31) Perigynia brown, smooth; beak longer than 0.2 mm.   210 Carex gmelinii
+ Perigynia gray-green, papillose; beak absent or less than 0.2 mm.   216 Carex buxbaumii
33 (31) Perigynia gray-green, conspicuously papillose throughout; beak minute, less than 0.2 mm.   217 Carex adelostoma
+ Perigynia straw colored, dark brown, or black, conspicuously papillose along distal margins; beak greater than 0.2 mm.   (34)
34 (33) Pistillate scales acute, dark brown or black to margins.   200 Carex atrata
+ Pistillate scales acute or short-mucronate, light to dark brown with hyaline margins.   (35)
35 (34) Perigynia dark brown, almost black; pistillate scales equaling perigynia.   203 Carex albonigra
+ Perigynia straw colored; pistillate scales shorter than perigynia.   228 Carex specuicola

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