View source for Cyperus

{{Treatment/ID
|accepted_name=Cyperus
|accepted_authority=Linnaeus
|publications={{Treatment/Publication
|title=Sp. Pl.
|place=1: 44. 1753
|year=1753
}}, {{Treatment/Publication
|title=Gen. Pl. ed.
|place=5, 26. 1754
|year=1754
}}
|common_names=Umbrella-sedge;flatsedge
|basionyms=
|synonyms=
|hierarchy=Cyperaceae;Cyperus
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Cyperaceae]]</div><div class="higher-taxon"><small>genus</small>[[Cyperus]]</div></div>
|etymology=Greek kupeiros, name for Eurasian Cyperus longus Linnaeus
|volume=Volume 23
|mention_page=page 7, 154, 162, 163, 164, 168, 170, 184
|treatment_page=page 141
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Herbs,</b> perennial or less often annual, cespitose or not, rhizomatous, stoloniferous, rarely tuberous. <b>Culms</b> solitary or not, trigonous or round, glabrous or scabridulous with extrorse or antrorse (rarely retrorse) prickles. <b>Leaves</b> usually basal; ligules absent; blades keeled abaxially, flat, V-, or inversely W-shaped in cross section. <b>Inflorescences</b> terminal, rarely pseudolateral, 1st order subumbellate to capitate, 2d order with spicate or digitately arranged spikelets, rarely a solitary spikelet; spikelets 1–150; 1st order rays unequal (rarely equal) in length, produced singly from the axils of inflorescence bracts; involucral bracts 1–22, spirally arranged at culm apex, spreading to erect, leaflike. <b>Spikelets</b>: scales to 76, distichous, each subtending flower, cylindric to compressed, borne spicately or digitately at ends of rays (occasionally proliferous). <b>Flowers</b> bisexual [rarely unisexual], in axils of distichous floral scales, bases often decurrent onto rachilla as ± hyaline wings; perianth absent; stamens 1–3; styles linear, 2–3-fid, base deciduous or persistent; stigmas 2–3. <b>Achenes</b> biconvex, flattened, or trigonous.</span><!--

-->{{Treatment/Body
|distribution=Pantemperate and tropical.
|discussion=<p>Species ca. 600 (96 in the flora).</p>
|tables=
|references={{Treatment/Reference
|id=carter1984a
|text=Carter, J. R. 1984. A Systematic Study of the New World Species of Section Umbellati of Cyperus. Ph.D. dissertation. Vanderbilt University.
}}{{Treatment/Reference
|id=corcoran1941a
|text=Corcoran, M. L. 1941. A revision of the subgenus Pycreus in North and South America. Catholic Univ. Amer., Biol. Ser. 37: 1–68.
}}{{Treatment/Reference
|id=denton1978b
|text=Denton, M. F. 1978b. The Luzulae group of Cyperus (Cyperaceae). Contr. Univ. Michigan Herb. 11: 197–271.
}}{{Treatment/Reference
|id=horvat1941a
|text=Horvat, M. L. 1941. A revision of the subgenus Mariscus found in the United States. Catholic Univ. Amer., Biol. Ser. 33: 1–147.
}}{{Treatment/Reference
|id=marcks1972a
|text=Marcks, B. G. 1972. Population Studies of North American Cyperus Section Laxiglumi (Cyperaceae). Ph.D. dissertation. University of Wisconsin.
}}{{Treatment/Reference
|id=marcks1974a
|text=Marcks, B. G. 1974. Preliminary reports on the flora of Wisconsin, no. 66. Cyperaceae II—Sedge family II. The genus Cyperus—the umbrella sedges. Trans. Wisconsin Acad. Sci. 62: 261–284.
}}{{Treatment/Reference
|id=mcgivney1938a
|text=McGivney, M. V. 1938. A revision of the subgenus Eucyperus found in the United States. Catholic Univ. Amer., Biol. Ser. 26: 1–74.
}}{{Treatment/Reference
|id=tucker1983a
|text=Tucker, G. C. 1983. The taxonomy of Cyperus (Cyperaceae) in Costa Rica and Panama. Syst. Bot. Mongr. 2: 1–85.
}}{{Treatment/Reference
|id=tucker1993a
|text=Tucker, G. C. and R. McVaugh. 1993. Cyperus. In: R. McVaugh and W. R. Anderson, eds. 1974+. Flora Novo-Galiciana: A Descriptive Account of the Vascular Plants of Western Mexico. 8+ vols. Ann Arbor. Vol. 13, pp. 270–344.
}}{{Treatment/Reference
|id=tucker1994a
|text=Tucker, G. C. 1994. A revision of the Mexican species of Cyperus L. (Cyperaceae). Syst. Bot. Monogr. 43: 1–214.
}}
}}<!--

--><div class="treatment-key">
==Keys==
<div class="treatment-key-group">
  <h3 class="treatment-key-header" id="key-0">Key to Subgenera</h3>  
{| class="wikitable fna-keytable"
|-id=key-0-1
|1
|Stigmas 2 (3 in C. serotinus); achenes biconvex.
|[[#key-0-2| > 2]]
|-id=key-0-1
|1
|Stigmas 3; achenes trigonous, plano-convex, or terete.
|[[#key-0-3| > 3]]
|-id=key-0-2
|2
|Achenes laterally flattened, borne with edge toward rachilla.
|[[Cyperus subg. Pycreus|Cyperus subg. Pycreus]]
|-id=key-0-2
|2
|Achenes dorsiventrally flattened, borne with face toward rachilla.
|[[Cyperus subg. Juncellus|Cyperus subg. Juncellus]]
|-id=key-0-3
|3
|Spikelets borne in digitate clusters (rarely singly) or in umbellate or glomerulate heads.
|[[Cyperus subg. Pycnostachys|Cyperus subg. Pycnostachys]]
|-id=key-0-3
|3
|Spikelets borne in spikes on conspicuous rachis.
|[[#key-0-4| > 4]]
|-id=key-0-4
|4
|Rachilla continuous or articulate only at base.
|[[Cyperus subg. Cyperus|Cyperus subg. Cyperus]]
|-id=key-0-4
|4
|Rachilla articulate at base of each scale, mature spikelet disarticulating into segments consisting of scale, internode, and rachilla wings.
|[[Cyperus subg. Diclidium|Cyperus subg. Diclidium]]
|}
</div><!--
--><div class="treatment-key-group">
  <h3 class="treatment-key-header" id="key-1">Artificial key to species</h3>
{| class="wikitable fna-keytable"
|-id=key-1-1
|1
|Stigmas 2; achenes biconvex to flattened, subcylindric, or cylindric
|[[#key-1-2| > 2]]
|-id=key-1-1
|1
|Stigmas 3; achenes usually trigonous
|[[#key-1-15| > 15]]
|-id=key-1-2
|2
|Achenes dorsiventrally flattened, borne with face toward rachilla
|[[#key-1-3| > 3]]
|-id=key-1-2
|2
|Achenes laterally flattened, biconvex, or subcylindric, borne with edge toward rachilla
|[[#key-1-5| > 5]]
|-id=key-1-3
|3
|Rays absent or sometimes 1, at most 2 mm; inflorescence capitate, appearing lateral; longest inflorescence bract erect, like continuation of culm
|[[Cyperus laevigatus|Cyperus laevigatus]]
|-id=key-1-3
|3
|Rays 2–26; inflorescence spicate, not appearing lateral; longest inflorescence bracts horizontal to ascending at 45°
|[[#key-1-4| > 4]]
|-id=key-1-4
|4
|Inflorescence bracts 5–25 cm; culms 50–100 cm; spikes ovoid; achenes 1.4–1.6 mm
|[[Cyperus serotinus|Cyperus serotinus]]
|-id=key-1-4
|4
|Inflorescence bracts 20–100 cm; culms 150–250 cm; spikes cylindric; achenes 0.9 mm
|[[Cyperus alopecuroides|Cyperus alopecuroides]]
|-id=key-1-5
|5
|Apex of floral scales with excurved awn 0.3–0.5 mm; stamens 1–2; achenes 0.6 mm; Florida
|[[Cyperus pumilus|Cyperus pumilus]]
|-id=key-1-5
|5
|Apex of floral scales with or without mucro; stamens 2–3; achenes (0.7–)1–1.6 mm; widespread
|[[#key-1-6| > 6]]
|-id=key-1-6
|6
|Achenes oblong with truncate apex, subcylindric, not much laterally compressed to biconvex or ± cylindric
|[[#key-1-7| > 7]]
|-id=key-1-6
|6
|Achenes ovoid, obovoid, or ellipsoid with rounded or subacute apex, laterally flattened or biconvex
|[[#key-1-9| > 9]]
|-id=key-1-7
|7
|Anthers 0. 1–0.2 mm; styles 0.1–0.3(–0.4) mm; stigmas 0.3–0.4 m
|[[Cyperus fugax|Cyperus fugax]]
|-id=key-1-7
|7
|Anthers (0.4–)0.5–0.8 mm; styles 0.6–2.1 mm; stigmas 1–2 mm
|[[#key-1-8| > 8]]
|-id=key-1-8
|8
|Floral scales 1.5–2.4 × 1–1.4 mm; achenes 0.8–1.2 × 0.4–0.6 mm
|[[Cyperus polystachyos|Cyperus polystachyos]]
|-id=key-1-8
|8
|Floral scales 2.7–3.6 × 1.6–1.8 mm; achenes 1.2–1.6 × 0.6–0.9 mm
|[[Cyperus filicinus|Cyperus filicinus]]
|-id=key-1-9
|9
|Plants annual; culms 30–75 cm; floral scales with conspicuous clear border, ovate, loosely imbricate, each barely overlapping next, spikelet margins appearing serrate
|[[Cyperus flavicomus|Cyperus flavicomus]]
|-id=key-1-9
|9
|Plants perennial or annual; culms 4–40(–95) cm; floral scales without clear border, oblong, closely imbricate, spikelet margins appearing entire
|[[#key-1-10| > 10]]
|-id=key-1-10
|10
|Surface of achenes with network of ridges forming rectangular, longitudinally elongate cells and transverse undulations; achenes broadly obovoid, black or reddish brown; stamens 3
|[[Cyperus flavescens|Cyperus flavescens]]
|-id=key-1-10
|10
|Surface of achene with network of ridges forming isodiametric or square cells, without transverse undulations; achenes ellipsoid or obovoid, brown or black; stamens 2 or 3
|[[#key-1-11| > 11]]
|-id=key-1-11
|11
|Floral scales yellow or yellowish brown, never purple or purple-tinged
|[[Cyperus lanceolatus|Cyperus lanceolatus]]
|-id=key-1-11
|11
|Floral scales brown to nearly black or castaneous, sometimes hyaline or yellow, then purple-tinged
|[[#key-1-12| > 12]]
|-id=key-1-12
|12
|Plants perennial with slender rhizomes; floral scales castaneous, blackish or occasionally light brown; achenes ovoid to ellipsoid
|[[#key-1-13| > 13]]
|-id=key-1-12
|12
|Plants annual with fibrous roots; floral scales brown (rarely yellow or stramineous) or reddish brown; achenes obovoid to ovoid
|[[#key-1-14| > 14]]
|-id=key-1-13
|13
|Achenes 1.2–1.4 mm; anthers 0.6–0.8 mm; Oklahoma to Oregon, southward
|[[Cyperus melanostachyus|Cyperus melanostachyus]]
|-id=key-1-13
|13
|Achenes 1–1.4 mm; anthers 0.3–0.6 mm; Alabama, Georgia, Louisiana, Mississippi
|[[Cyperus sanguinolentus|Cyperus sanguinolentus]]
|-id=key-1-14
|14
|Floral scales 1.9–2.7 × 1.8–2.3 mm; styles 0.6–1 mm; stigmas 1–1.5 mm
|[[Cyperus bipartitus|Cyperus bipartitus]]
|-id=key-1-14
|14
|Floral scales 2.5-3 × 1.6–1.9 mm; styles 0.3–0.5 mm; stigmas 2.2–3.1 mm
|[[Cyperus diandrus|Cyperus diandrus]]
|-id=key-1-15
|15
|Spikelets in digitate clusters (rarely solitary), or in umbellate or glomerulate heads
|[[#key-1-16| > 16]]
|-id=key-1-15
|15
|Spikelets in spikes on conspicuous rachis
|[[#key-1-49| > 49]]
|-id=key-1-16
|16
|Floral scales 2-keeled in proximal 30–60%
|[[#key-1-17| > 17]]
|-id=key-1-16
|16
|Floral scales not 2-keeled, conduplicate (or broadly rounded)
|[[#key-1-28| > 28]]
|-id=key-1-17
|17
|Leaves without blades; inflorescence bracts ca. 20, all ± horizontal; stamens 3
|[[Cyperus involucratus|Cyperus involucratus]]
|-id=key-1-17
|17
|Leaves with blades; inflorescence bracts 2–10(–40), at various angles; stamens 1 (rarely 2)
|[[#key-1-18| > 18]]
|-id=key-1-18
|18
|Culms trigonous, harshly scabrid on angles only; leaf blades and bracts with conspicuous cross ribs
|[[#key-1-19| > 19]]
|-id=key-1-18
|18
|Culms trigonous, subterete, or terete, glabrous or scabridulous; leaf blades and bracts without cross ribs
|[[#key-1-20| > 20]]
|-id=key-1-19
|19
|Rays 6–12; floral scales oblanceolate, (1.3–)1.5–2(–2.4) mm; achenes 1.2–1.5 mm
|[[Cyperus virens|Cyperus virens]]
|-id=key-1-19
|19
|Rays 3–5; floral scales ovate, 1.4–1.6 mm; achenes 1–1.2 mm
|[[Cyperus drummondii|Cyperus drummondii]]
|-id=key-1-20
|20
|Culms scabridulous with retrorse prickles
|[[Cyperus surinamensis|Cyperus surinamensis]]
|-id=key-1-20
|20
|Culms glabrous or with antrorse or extrorse prickles
|[[#key-1-21| > 21]]
|-id=key-1-21
|21
|Achenes with swollen, spongy base
|[[Cyperus distinctus|Cyperus distinctus]]
|-id=key-1-21
|21
|Achenes without swollen, spongy base
|[[#key-1-22| > 22]]
|-id=key-1-22
|22
|Achenes broadly ellipsoid, stipitate or cuneate
|[[#key-1-23| > 23]]
|-id=key-1-22
|22
|Achenes narrowly ellipsoid to linear, not or barely stipitate
|[[#key-1-25| > 25]]
|-id=key-1-23
|23
|Plants annual; longest inflorescence bract erect to ascending; anther 0.5 mm; widespread
|[[Cyperus acuminatus|Cyperus acuminatus]]
|-id=key-1-23
|23
|Plants perennial; longest inflorescence bract horizontal to ascending at 30°; anther 0.8–1.2 mm; Gulf or Pacific coasts
|[[#key-1-24| > 24]]
|-id=key-1-24
|24
|Floral scales 2–2.3 mm, declined 30–45° from rachilla; achenes stipitate
|[[Cyperus eragrostis|Cyperus eragrostis]]
|-id=key-1-24
|24
|Floral scales (1.2–)1.5–2 mm, declined (45–)60–90° from rachilla; achenes cuneate to stipitate
|[[Cyperus ochraceus|Cyperus ochraceus]]
|-id=key-1-25
|25
|Longest bract erect, appearing as continuation of culm; spikelets reddish
|[[Cyperus reflexus|Cyperus reflexus]]
|-id=key-1-25
|25
|Longest bract (horizontal-)ascending at 30–60(–75)°; spikelets greenish white
|[[#key-1-26| > 26]]
|-id=key-1-26
|26
|Achenes linear (slightly curved); spikelets ovoid
|[[Cyperus pseudovegetus|Cyperus pseudovegetus]]
|-id=key-1-26
|26
|Achenes ellipsoid to narrowly ellipsoid; spikelets linear to broadly ellipsoid
|[[#key-1-27| > 27]]
|-id=key-1-27
|27
|Floral scales 1–1.5 mm; bracts horizontal to ascending at 30°
|[[Cyperus surinamensis|Cyperus surinamensis]]
|-id=key-1-27
|27
|Floral scales (1.2–)1.4–1.6(–1.8) mm; bracts ascending at 45–60(–75)°
|[[Cyperus entrerianus|Cyperus entrerianus]]
|-id=key-1-28
|28
|Plants annual
|[[#key-1-29| > 29]]
|-id=key-1-28
|28
|Plants perennial (C. gracilis annual or perennial)
|[[#key-1-34| > 34]]
|-id=key-1-29
|29
|Apex of floral scale emarginate, cuspidate
|[[#key-1-30| > 30]]
|-id=key-1-29
|29
|Apex of floral scales acute or obtuse, emarginate, muticous, mucronate, mucronulate, or cuspidate
|[[#key-1-31| > 31]]
|-id=key-1-30
|30
|Scale cusp 0.3(–0.5) mm; achenes 0.8–0.9 mm; anthers 0.3 mm; Arizona
|[[Cyperus amabilis|Cyperus amabilis]]
|-id=key-1-30
|30
|Scale cusp 0.6–1.2 mm; achenes (0.5–)0.6 mm; anthers 0.1(–0.2) mm; se United States
|[[Cyperus cuspidatus|Cyperus cuspidatus]]
|-id=key-1-31
|31
|Scale apex mucronulate or mucronate
|[[#key-1-32| > 32]]
|-id=key-1-31
|31
|Scale apex cuspidate
|[[#key-1-33| > 33]]
|-id=key-1-32
|32
|Spikelets 30–120 per head; floral scales 0.6–0.8 mm; styles 0. 1 mm
|[[Cyperus difformis|Cyperus difformis]]
|-id=key-1-32
|32
|Spikelets 3–12 per head; floral scales 0.9–1.1 mm; styles 0.3–0.4 mm
|[[Cyperus fuscus|Cyperus fuscus]]
|-id=key-1-33
|33
|Achenes 0.7–0.8(–1.1) mm; cusp excurved; stamen 1; floral scales laterally strongly 3–4-ribbed
|[[Cyperus squarrosus|Cyperus squarrosus]]
|-id=key-1-33
|33
|Achenes 1–1.5 mm; cusp straight; stamens 3; floral scales laterally weakly 1–2-ribbed
|[[Cyperus compressus|Cyperus compressus]]
|-id=key-1-34
|34
|Inflorescences unbranched; achene apex emarginate; California
|[[Cyperus gracilis|Cyperus gracilis]]
|-id=key-1-34
|34
|Inflorescences branched or unbranched; achene apex not emarginate; widespread
|[[#key-1-35| > 35]]
|-id=key-1-35
|35
|Floral scales laterally milky white (infrequently pale greenish white, brownish or bronzy white), laterally ribless; culms 0.4–1 mm wide; rays absent, inflorescence capitate; sw United States mountains
|[[Cyperus seslerioides|Cyperus seslerioides]]
|-id=key-1-35
|35
|Floral scales laterally light to dark reddish brown or stramineous, laterally 1–5-ribbed; culms (0.4–)1–4 mm wide; rays present or absent; inflorescences usually not capitate; widespread
|[[#key-1-36| > 36]]
|-id=key-1-36
|36
|Achenes with granular to papillose surface; inflorescence with 2d order (and 3d order) rays; leaves often without blades
|[[#key-1-37| > 37]]
|-id=key-1-36
|36
|Achenes with smooth, puncticulate, or papillose surface; inflorescence usually with primary (rarely 2d order) rays; leaf blades present
|[[#key-1-38| > 38]]
|-id=key-1-37
|37
|Rays 5–15; anthers 0.3–0.5 mm
|[[Cyperus haspan|Cyperus haspan]]
|-id=key-1-37
|37
|Rays 100–250; anthers 1–1.2 mm
|[[Cyperus prolifer|Cyperus prolifer]]
|-id=key-1-38
|38
|Rachilla with wings 0.6 mm wide
|[[#key-1-39| > 39]]
|-id=key-1-38
|38
|Rachilla wingless or with narrow wings 0.1–0.2 mm wide
|[[#key-1-40| > 40]]
|-id=key-1-39
|39
|Spikelets compressed; achenes ellipsoid; inflorescence bracts 3–8; New Hampshire to Georgia
|[[Cyperus grayi|Cyperus grayi]]
|-id=key-1-39
|39
|Spikelets terete; achenes obovoid; inflorescence bracts 2–3; Florida
|[[Cyperus filiformis|Cyperus filiformis]]
|-id=key-1-40
|40
|Longest bract ± erect
|[[#key-1-41| > 41]]
|-id=key-1-40
|40
|Longest bract oblique, horizontal or reflexed
|[[#key-1-43| > 43]]
|-id=key-1-41
|41
|Floral scales laterally 1-ribbed; achenes 0.7–0.8 mm
|[[Cyperus onerosus|Cyperus onerosus]]
|-id=key-1-41
|41
|Floral scales laterally 2–4-ribbed; achenes 1.4–2.4 mm
|[[#key-1-42| > 42]]
|-id=key-1-42
|42
|Achenes broadly ellipsoid; floral scale apex with cusp 0.3–1 mm (in distal scales)
|[[Cyperus schweinitzii|Cyperus schweinitzii]]
|-id=key-1-42
|42
|Achenes ovoid to obovoid; floral scale apex with mucro 0.1–0.3 m
|[[Cyperus sphaerolepis|Cyperus sphaerolepis]]
|-id=key-1-43
|43
|Plants with slender stolons, growing in wet soil
|[[#key-1-44| > 44]]
|-id=key-1-43
|43
|Plants with cormose bases, short, fibrous rhizomes, growing in dry soils
|[[#key-1-45| > 45]]
|-id=key-1-44
|44
|Floral scales ovate-elliptic, 20–60; spikelets not proliferous; Louisiana to North Carolina
|[[Cyperus lecontei|Cyperus lecontei]]
|-id=key-1-44
|44
|Floral scales ovate, 3–20(–50); spikelets often proliferous; New Brunswick to South Carolina, Indiana
|[[Cyperus dentatus|Cyperus dentatus]]
|-id=key-1-45
|45
|Longest bract oblique
|[[#key-1-46| > 46]]
|-id=key-1-45
|45
|Longest bract horizontal to reflexed
|[[#key-1-47| > 47]]
|-id=key-1-46
|46
|Apex of floral scale without mucro; achenes 2–2.4 mm; anthers 1–1.2 mm
|[[Cyperus grayoides|Cyperus grayoides]]
|-id=key-1-46
|46
|Apex of floral scale with mucro 0.1–0.2 mm; achenes 1.5–2 mm; anthers 0.5–0.7 mm
|[[Cyperus houghtonii|Cyperus houghtonii]]
|-id=key-1-47
|47
|Floral scales reddish; rachilla wings 0.2 mm wide; Florida Keys
|[[Cyperus fuligineus|Cyperus fuligineus]]
|-id=key-1-47
|47
|Floral scales light brown, off-white, or stramineous; rachilla wingless; widespread
|[[#key-1-48| > 48]]
|-id=key-1-48
|48
|Anthers 0.8–1 mm; achenes 0.5–0.8 mm wide; floral scales yellowish; se United States
|[[Cyperus filiculmis|Cyperus filiculmis]]
|-id=key-1-48
|48
|Anthers 0.3–0.6 mm; achenes 0.8–1.2 mm wide; floral scales off-white to light reddish brown; widespread
|[[Cyperus lupulinus|Cyperus lupulinus]]
|-id=key-1-49
|49
|Rachilla articulate at base of each scale, mature spikelet disarticulating into segments, each consisting of scale, internode, and rachilla wings
|[[#key-1-50| > 50]]
|-id=key-1-49
|49
|Rachilla not articulate, or articulate only at base
|[[#key-1-51| > 51]]
|-id=key-1-50
|50
|Plants annual or short-lived perennial; spikelets (10–)20–60(–100) per spike; rays frequently present; achenes narrowly ellipsoid to oblong, (1–)1.2–1.5(–1.9) mm; widespread
|[[Cyperus odoratus|Cyperus odoratus]]
|-id=key-1-50
|50
|Plants perennial; spikelets 2–8; rays usually absent; achenes obovoid, 2 mm; Florida
|[[Cyperus filiformis|Cyperus filiformis]]
|-id=key-1-51
|51
|Floral scales with straight, excurved mucronate, or cuspidate apex 0.1–1.3 mm (basal scales often mucronate, with apex to 0.2 mm)
|[[#key-1-52| > 52]]
|-id=key-1-51
|51
|Floral scales entire or emarginate, with mucronulate apex at most 0.3 mm
|[[#key-1-60| > 60]]
|-id=key-1-52
|52
|Floral scales persistent, appressed, 3 or more mm; spikelets subcylindric; rachilla winged
|[[#key-1-53| > 53]]
|-id=key-1-52
|52
|Floral scales deciduous, spreading, usually less than 3 mm; spikelets quadrangular; rachilla wingless or wings at most 0.4 mm
|[[#key-1-55| > 55]]
|-id=key-1-53
|53
|Spikelets  (4–)6–8(–14)-flowered, (8–)12–15(–24) mm; floral scales golden brown, stramineous, or hyaline; terminal scale conduplicate; Florida, Texas
|[[Cyperus lentiginosus|Cyperus lentiginosus]]
|-id=key-1-53
|53
|Spikelets 1–3(–5)-flowered, 4–10 mm; floral scales green or hyaline, stramineous, or reddish; terminal sterile scale involute, frequently excurved; Mississippi  to Arizona
|[[#key-1-54| > 54]]
|-id=key-1-54
|54
|Longest spikelets (2.2–)4–10(–18) mm; distal floral scales with glabrous midrib and mucro 0.1–0.3(–0.5) mm; anthers (0.3–)0.4–0.6 mm
|[[Cyperus retroflexus|Cyperus retroflexus]]
|-id=key-1-54
|54
|Longest spikelets 9–21 mm; distal floral scales with scabrid midrib and mucro 0.6–1.9 mm; anthers 0.5–1.3 mm
|[[Cyperus floribundus|Cyperus floribundus]]
|-id=key-1-55
|55
|Plants perennial, not cespitose; rhizomes indurate, to 4 cm; floral scales weakly 3–7(–9)-ribbed, mostly medially
|[[#key-1-56| > 56]]
|-id=key-1-55
|55
|Plants annual (C. oxylepis perennial), cespitose with fibrous roots; rhizomes absent; floral scales 5–13-ribbed (C. oxylepis 2–3-ribbed) nearly to margins
|[[#key-1-57| > 57]]
|-id=key-1-56
|56
|Floral scales ovate-lanceolate, dull white, stramineous, or reddish brown; achenes 1.4–1.6 mm; anthers 0.4–0.9 mm; Arizona, New Mexico
|[[Cyperus dipsaceus|Cyperus dipsaceus]]
|-id=key-1-56
|56
|Floral scales broadly ovate to oblong-ovate, stramineous or dull whitish; achenes 2–2.4 mm; anthers 0.8–1.4 mm; widespread
|[[Cyperus schweinitzii|Cyperus schweinitzii]]
|-id=key-1-57
|57
|Floral scales strongly ribbed, (0.5–)1–2 mm wide; achenes 0.6 mm or less wide; stamens 1(–2)
|[[#key-1-58| > 58]]
|-id=key-1-57
|57
|Floral scales weakly ribbed, 1.5–3.6 mm wide; achenes 0.9–1.4 mm wide (0.5–0.8 mm wide in C. oxylepis); stamens 3
|[[#key-1-59| > 59]]
|-id=key-1-58
|58
|Floral scales 0.5–1 mm wide, (5–)7–9(–11)-ribbed; filaments 1.5 mm; anthers 0.2–0.3 mm; widespread
|[[Cyperus squarrosus|Cyperus squarrosus]]
|-id=key-1-58
|58
|Floral scales 1–2 mm wide, 5–13-ribbed; filaments 1.5 mm; anthers 0.8–1 mm; se United States
|[[Cyperus granitophilus|Cyperus granitophilus]]
|-id=key-1-59
|59
|Achenes obovoid, base cuneate to stipitate, not spongy, apex obtuse to emarginate; leaves flat to V-shaped, margins not involute; plants nonviscous when living
|[[Cyperus compressus|Cyperus compressus]]
|-id=key-1-59
|59
|Achenes ellipsoid, base stipitate, spongy, apex acute with beak 0.5–1.2 mm; leaves not flat to V-shaped, margins involute; plants viscous when living
|[[Cyperus oxylepis|Cyperus oxylepis]]
|-id=key-1-60
|60
|Spikelets linear, 0.8–1.9 mm wide; apex of scale barely reaching or as much as 0.4 mm from base of next scale
|[[#key-1-61| > 61]]
|-id=key-1-60
|60
|Spikelets oblong-ovate to linear-oblong, (0.5–)2–3(–4.5) mm wide; apex of scale equaling or surpassing base of next scale
|[[#key-1-62| > 62]]
|-id=key-1-61
|61
|Rachilla with hyaline or bronze, carmine, or yellowish thickened wings clasping achene; widespread
|[[Cyperus odoratus|Cyperus odoratus]]
|-id=key-1-61
|61
|Rachilla wingless or with narrow, hyaline wings not clasping achene; Florida, North Carolina
|[[Cyperus distans|Cyperus distans]]
|-id=key-1-62
|62
|Floral scales spreading or appressed (at least proximal portions of spikelet); spikelets compressed (2 or more times wide as thick)
|[[#key-1-63| > 63]]
|-id=key-1-62
|62
|Floral scales appressed; spikelets quadrangular to subterete (1–1.5 times as wide as thick)
|[[#key-1-88| > 88]]
|-id=key-1-63
|63
|Floral scales obovate-orbiculate, apex emarginate; styles less than 0.1 mm
|[[#key-1-64| > 64]]
|-id=key-1-63
|63
|Floral scales elliptic, oblong, or ovate, apex acute to obtuse; styles 0.2–3.6 mm
|[[#key-1-65| > 65]]
|-id=key-1-64
|64
|Spikelets ascending-appressed; rachilla with successive floral scales 0.7–0.9 mm apart (on same side of rachilla); scale apex with mucro 0.05–0.12 mm
|[[Cyperus iria|Cyperus iria]]
|-id=key-1-64
|64
|Spikelets spreading; rachilla with successive floral scales 1.1–1.5 mm apart; scale apex with mucro 0.2–0.25 mm
|[[Cyperus microiria|Cyperus microiria]]
|-id=key-1-65
|65
|Rachilla with hyaline, whitish, or stramineous wings 0.2–0.6(–1) mm wide
|[[#key-1-66| > 66]]
|-id=key-1-65
|65
|Rachilla wingless or with wings less than 0.2 mm wide
|[[#key-1-76| > 76]]
|-id=key-1-66
|66
|Culms terete (at least in basal 2/3), nodose-septate when dried; inflorescence bracts 2(–4), erect; leaf usually reduced to sheath
|[[Cyperus articulatus|Cyperus articulatus]]
|-id=key-1-66
|66
|Culms trigonous, not nodose-septate; inflorescence bracts 2–8, ± horizontal to ascending at 45° to reflexed; leaf blades present
|[[#key-1-67| > 67]]
|-id=key-1-67
|67
|Floral scales persistent; rachilla persistent; elongate stolons to 15 cm, bearing tubers
|[[#key-1-68| > 68]]
|-id=key-1-67
|67
|Floral scales deciduous; rachilla deciduous or persistent; rhizomes 0–5 cm, tubers absent
|[[#key-1-69| > 69]]
|-id=key-1-68
|68
|Floral scales yellowish brown to dark brown; base of culm soft stolons spongy, flexible when dried
|[[Cyperus esculentus|Cyperus esculentus]]
|-id=key-1-68
|68
|Floral scales purple to reddish brown, with green midrib; base of culm indurate; stolons indurate, wiry, springy when dried
|[[Cyperus rotundus|Cyperus rotundus]]
|-id=key-1-69
|69
|Culms 50–300 cm; 2d order rays 1–10 cm, distinctly flattened; 3d order rays 0.5–3 cm; coastal Louisiana
|[[Cyperus prolixus |Cyperus prolixus]]
|-id=key-1-69
|69
|Culms to 100 cm; 2d order rays absent or less than 5 cm, terete to trigonous; 3d order rays absent; widespread
|[[#key-1-70| > 70]]
|-id=key-1-70
|70
|Culms trigonous, angles scabrid; Arizona
|[[Cyperus hypopitys|Cyperus hypopitys]]
|-id=key-1-70
|70
|Culms trigonous, glabrous or with a few prickles subapically; widespread
|[[#key-1-17| > 71]]
|-id=key-1-71
|71
|Achenes coarsely punctate; beaches, Florida, Georgia
|[[Cyperus planifolius|Cyperus planifolius]]
|-id=key-1-71
|71
|Achenes glabrous or puncticulate; widespread
|[[#key-1-72| > 72]]
|-id=key-1-72
|72
|Base of culm swollen, cormlike
|[[#key-1-73| > 73]]
|-id=key-1-72
|72
|Base of culm not swollen
|[[#key-1-74| > 74]]
|-id=key-1-73
|73
|Floral scales 3.2–4.5(–6) mm; stigmas 3–4 mm
|[[Cyperus strigosus|Cyperus strigosus]]
|-id=key-1-73
|73
|Floral scales 2–2.8 mm; stigmas 1–2 mm
|[[Cyperus grayi|Cyperus grayi]]
|-id=key-1-74
|74
|Rhizomes present; achenes 0.4–0.5 mm wide; anthers 1.5–2 mm; Great Plains
|[[Cyperus setigerus|Cyperus setigerus]]
|-id=key-1-74
|74
|Rhizomes absent; achenes 0.6–0.9 mm wide; anthers 0.3–0.6 mm; sw, se United States
|[[#key-1-75| > 75]]
|-id=key-1-75
|75
|Achenes broadly ellipsoid; anthers 0.3–0.4 mm; floral scales red, reddish purple, or reddish brown; sw United States
|[[Cyperus parishii|Cyperus parishii]]
|-id=key-1-75
|75
|Achenes narrowly ellipsoid; anthers 0.6 mm; floral scales greenish white, often reddish brown speckled; Florida
|[[Cyperus sphacelatus|Cyperus sphacelatus]]
|-id=key-1-76
|76
|Leaf blades involute; plants viscous when living
|[[Cyperus elegans|Cyperus elegans]]
|-id=key-1-76
|76
|Leaf blades flat or V-shaped; plants not viscous
|[[#key-1-77| > 77]]
|-id=key-1-77
|77
|Longest inflorescence bract ± erect
|[[#key-1-78| > 78]]
|-id=key-1-77
|77
|Longest inflorescence bract oblique, horizontal, or reflexed
|[[#key-1-79| > 79]]
|-id=key-1-78
|78
|Floral scales broadly ovate to oblong-ovate, apex with cusp 0.3–1 mm; achenes 2–2.4 mm; widespread
|[[Cyperus schweinitzii|Cyperus schweinitzii]]
|-id=key-1-78
|78
|Floral scales ovate-deltate to orbiculate, apex with cusp 0.1–0.3 mm; achenes 1.4–1.6(–1.9) mm; Arizona, New Mexico, Texas
|[[Cyperus sphaerolepis|Cyperus sphaerolepis]]
|-id=key-1-79
|79
|Longest inflorescence bract ± horizontal to reflexed
|[[#key-1-80| > 80]]
|-id=key-1-79
|79
|Longest inflorescence bract oblique, ascending, or horizontal
|[[#key-1-83| > 83]]
|-id=key-1-80
|80
|Spikes cylindric
|[[Cyperus fendlerianus|Cyperus fendlerianus]]
|-id=key-1-80
|80
|Spikes ovoid (hemispheric in C. fuligineus)
|[[#key-1-81| > 81]]
|-id=key-1-81
|81
|Floral scales reddish brown, 1.5–2.2 mm; Florida Keys
|[[Cyperus fuligineus|Cyperus fuligineus]]
|-id=key-1-81
|81
|Floral scales light brown to yellow, 2.5–4 mm; widespread
|[[#key-1-82| > 82]]
|-id=key-1-82
|82
|Anthers 0.8–1 mm; achenes 0.5–0.8 mm wide; floral scales yellowish to yellowish brown; se United States
|[[Cyperus filiculmis|Cyperus filiculmis]]
|-id=key-1-82
|82
|Anthers 0.3–0.6 mm; achenes 0.8–1.2 mm wide; floral scales off-white to light reddish brown; widespread
|[[Cyperus lupulinus|Cyperus lupulinus]]
|-id=key-1-83
|83
|Floral scales strongly ribbed laterally
|[[#key-1-84| > 84]]
|-id=key-1-83
|83
|Floral scales weakly ribbed laterally or ribless
|[[#key-1-85| > 85]]
|-id=key-1-84
|84
|Rachis hispidulous; achenes 1–1.2 mm; spikes loosely oblong-ovoid; wetlands, se United States
|[[Cyperus pilosus|Cyperus pilosus]]
|-id=key-1-84
|84
|Rachis glabrous; achenes 1.5–2 mm; spikes subglobose to broadly ovoid; uplands, ne, Great Lakes region
|[[Cyperus houghtonii|Cyperus houghtonii]]
|-id=key-1-85
|85
|Culms glabrous or nearly so
|[[#key-1-86| > 86]]
|-id=key-1-85
|85
|Culms scabrid or scabridulous
|[[#key-1-87| > 87]]
|-id=key-1-86
|86
|Rachis 10–20 mm; anthers 0.4–0.6 mm
|[[Cyperus spectabilis|Cyperus spectabilis]]
|-id=key-1-86
|86
|Rachis 2–6 mm; anthers 1–1.2 mm
|[[Cyperus grayoides|Cyperus grayoides]]
|-id=key-1-87
|87
|Floral scales (1.5–)1.8–2.4(–2.7) mm; achenes 1.3–1.8(–2.2) mm
|[[Cyperus manimae|Cyperus manimae]]
|-id=key-1-87
|87
|Floral scales 2.5–3 mm; achenes 0.5–0.6 mm wide
|[[Cyperus cephalanthus|Cyperus cephalanthus]]
|-id=key-1-88
|88
|Floral scales deciduous; rachilla persistent, rachilla wings deciduous along lateral edge, base remaining firmly attached even after achenes fall; 2d order rays frequently present; spikelets with (6–)12–20(–40) floral scales
|[[#key-1-89| > 89]]
|-id=key-1-88
|88
|Floral scales persistent; rachilla deciduous (mature spikelets falling as unit from rachis) or persistent, rachilla wings persistent; 2d order rays absent or present; spikelets with (1–)2–5 floral scales
|[[#key-1-92| > 92]]
|-id=key-1-89
|89
|Culms leafless, (55–)200–350(–500) cm; inflorescences to 80 cm; 2d order rays to 20 cm; anther connectives subulate, 0.2–0.5 mm
|[[#key-1-90| > 90]]
|-id=key-1-89
|89
|Culms leafy, (5–)50–150 cm; inflorescences (2.5–)20–40(–50) cm; 2d order rays absent or at most 5 cm; anther connectives blunt, at most 0.1 mm
|[[#key-1-91| > 91]]
|-id=key-1-90
|90
|Rays slender, drooping or arching; inflorescence bracts 3–8 cm
|[[Cyperus papyrus |Cyperus papyrus]]
|-id=key-1-90
|90
|Rays stiff, ascending to erect; inflorescence bracts (8–)20–45 cm
|[[Cyperus giganteus|Cyperus giganteus]]
|-id=key-1-91
|91
|Plants annual; culms typically less than 25 cm × 1–2.5 mm; floral scales 1.3–1.5 mm; achenes 0.4–0.6 mm; anthers 0.2–0.3 mm; widespread
|[[Cyperus erythrorhizos|Cyperus erythrorhizos]]
|-id=key-1-91
|91
|Plants perennial; culms 50–150 cm × 2–15 mm; floral scales 1.6–1.8 mm; achenes 0.9 mm; anthers 0.4–0.5 mm; Florida, Texas
|[[Cyperus digitatus|Cyperus digitatus]]
|-id=key-1-92
|92
|Spikes obtrulloid, obdeltoid to oblong-cylindric; spikelets, including distal, spreading to declined
|[[#key-1-93| > 93]]
|-id=key-1-92
|92
|Spikes cylindric, ellipsoid to obovoid, or globose; distal spikelets spreading or ascending, not declined
|[[#key-1-95| > 95]]
|-id=key-1-93
|93
|Culms glabrous; leaves and bracts glabrous except for marginal prickles; spikes ± 2 times long as wide; rachilla wing clasping achene for its entire length (therefore achene not visible in abaxial view); floral scales golden brown
|[[Cyperus hystricinus|Cyperus hystricinus]]
|-id=key-1-93
|93
|Culms (at least distal portions) densely scabridulous; leaves and bracts harshly scabrid or hirtellous on adaxial surface; spikes nearly as wide as long; rachilla wing clasping achene 3/4 or less of its length; floral scales grayish green to brown, often red-purple striate
|[[#key-1-94| > 94]]
|-id=key-1-94
|94
|Spikes loose, obtrulloid to obdeltoid; terminal scale not spinose; spikelets with 3–6(–8) floral scales; rays glabrous (rarely with a few antrorse hairs just proximal to spike); leaves and bracts with pubescence confined to midrib on abaxial side; rachilla wing papery with narrow, hyaline border, clasping achene for 3/4 its length; longest ray shorter than bracts; culm sharply angled
|[[Cyperus retrofractus|Cyperus retrofractus]]
|-id=key-1-94
|94
|Spikes tight, burlike, turbinate; terminal scale spinose; spikelets with 1(–2) floral scales; rays scabrid; leaves and bracts usually puberulent; rachilla wing hyaline, clasping achene ca. 1/2 its length; longest bract equaling or shorter than longest ray; culm obtusely trigonous to subterete
|[[Cyperus plukenetii|Cyperus plukenetii]]
|-id=key-1-95
|95
|Spikes densely cylindric (2–5 times longer than wide)
|[[#key-1-96| > 96]]
|-id=key-1-95
|95
|Spikes loosely to densely ovoid (1–2 times long as wide) or globose
|[[#key-1-104| > 104]]
|-id=key-1-96
|96
|Culms hispidulous on faces and angles distally, especially proximal to bracts; rays and rachis hispidulous; s Arizona
|[[Cyperus dentoniae|Cyperus dentoniae]]
|-id=key-1-96
|96
|Culms glabrous or occasionally with few prickles on angles only; rays and rachis glabrous; Florida or widespread
|[[#key-1-97| > 97]]
|-id=key-1-97
|97
|Culms, rays, and leaf blades papillose; leaves harshly scabrid on margins and midribs; Florida
|[[Cyperus ligularis|Cyperus ligularis]]
|-id=key-1-97
|97
|Culms, rays, and leaf blades not papillose; leaves scabridulous or glabrous on margins and midribs; widespread
|[[#key-1-98| > 98]]
|-id=key-1-98
|98
|Spikelets oblong, lanceoloid, or cylindric, 4–10 times as long as wide, 3–8 fertile floral scales; spikes 7–40 mm wide
|[[#key-1-99| > 99]]
|-id=key-1-98
|98
|Spikelets ellipsoid to subulate, 2–4 times long as wide, 1–2(–5) fertile floral scales; spikes 5–11 mm wide
|[[#key-1-101| > 101]]
|-id=key-1-99
|99
|Floral scales greenish or light brown, apices overlapping proximal 1/4–1/3 of next scale; spikes ovoid to oblong-cylindric
|[[Cyperus strigosus|Cyperus strigosus]]
|-id=key-1-99
|99
|Floral scales light brown to reddish brown, apices barely reaching base of next scale; spikes cylindric
|[[#key-1-100| > 100]]
|-id=key-1-100
|100
|Achenes narrowly oblong; floral scales light brown, bronze, or tawny; Gulf Coastal Plain
|[[Cyperus thyrsiflorus|Cyperus thyrsiflorus]]
|-id=key-1-100
|100
|Achenes ellipsoid; floral scales pale greenish white, or golden brown to deep brown, or reddish brown; mountains, Texas to Arizona
|[[Cyperus hermaphroditus|Cyperus hermaphroditus]]
|-id=key-1-101
|101
|Bracts horizontal to ascending or reflexed; achenes (1.5–)1.8–2.2 mm
|[[#key-1-102| > 102]]
|-id=key-1-101
|101
|Bracts ascending at ± 45°; achenes 1.5–1.8 mm
|[[#key-1-103| > 103]]
|-id=key-1-102
|102
|Bracts horizontal to slightly ascending; spikelets 3–5 mm; anthers 0.4–0.6 mm; widespread
|[[Cyperus aggregatus|Cyperus aggregatus]]
|-id=key-1-102
|102
|Bracts horizontal to strongly reflexed; spikelets 2.4–3.6 mm; anthers 0.6–0.8 mm; Arizona, New Mexico
|[[Cyperus pallidicolor|Cyperus pallidicolor]]
|-id=key-1-103
|103
|Achenes 0.7–1 mm wide; spikelets oblong-ellipsoid; Arizona
|[[Cyperus mutisii|Cyperus mutisii]]
|-id=key-1-103
|103
|Achenes 0.5 mm wide; spikelets narrowly ellipsoid to subulate; California
|[[Cyperus aggregatus|Cyperus regiomontanus, see C. aggregatus]]
|-id=key-1-104
|104
|Floral scales more than 3.5 mm; achenes more than 1.5 mm
|[[#key-1-105| > 105]]
|-id=key-1-104
|104
|Floral scales usually less than 4 mm; achenes usually less than 2 mm
|[[#key-1-108| > 108]]
|-id=key-1-105
|105
|Spikes densely globose or globose-ovoid
|[[Cyperus echinatus|Cyperus echinatus]]
|-id=key-1-105
|105
|Spikes ellipsoid to obovoid to loosely cylindric or oblong
|[[#key-1-106| > 106]]
|-id=key-1-106
|106
|Spikelets subquadrangular, subulate, with long, narrow terminal scale; leaves and bracts 3–6 mm wide, glabrous except for scabridulous margins; rhizomes well developed, thick
|[[Cyperus hystricinus|Cyperus hystricinus]]
|-id=key-1-106
|106
|Spikelets subterete, acute without long, narrow terminal scale; leaves and bracts often more than 10 mm wide, adaxial surfaces scabridulous; rhizomes poorly developed, short, hardly visible between approximate cormose culm bases
|[[#key-1-107| > 107]]
|-id=key-1-107
|107
|Spikes loose, 13–74 spikelets, each with (2–)3–6 floral scales; floral scales stramineous, red-purple striate, 4.5–5.3 mm; achenes straight, 5–6 times long as wide, 2.6–3.2 × 0.5–0.6 mm; anthers 1–1.5 mm
|[[Cyperus refractus|Cyperus refractus]]
|-id=key-1-107
|107
|Spikes dense, 50–90 spikelets, each with 3–6(–8) floral scales; floral scales whitish green, often yellow tinted, 4–4.6 mm; achenes conspicuously falciform, 3–4 times long as wide, 2.2–2.6 × 0.6–0.7 mm; anthers 0.7–1 mm
|[[Cyperus lancastriensis|Cyperus lancastriensis]]
|-id=key-1-108
|108
|Spikes with ± parallel sides, mostly more than 25 mm; spikelets ± quadrangular
|[[#key-1-109| > 109]]
|-id=key-1-108
|108
|Spikes with curved (convex) sides, mostly less than 20 mm; spikelets somewhat compressed
|[[#key-1-112| > 112]]
|-id=key-1-109
|109
|Spikelets narrowly ellipsoid, 1.5–2 mm wide
|[[Cyperus tetragonus|Cyperus tetragonus]]
|-id=key-1-109
|109
|Spikelets oblong to linear, 0.6–1.6 mm wide
|[[#key-1-110| > 110]]
|-id=key-1-110
|110
|Achenes ellipsoid, sessile or nearly so; stigmas 1–1.5 mm; Texas to Arizona
|[[Cyperus hermaphroditus|Cyperus hermaphroditus]]
|-id=key-1-110
|110
|Achenes narrowly oblong, stipitate, stipe 0.1–0.2 mm; stigmas (0.5–)2–3(–4) mm; Georgia to Texas
|[[#key-1-111| > 111]]
|-id=key-1-111
|111
|Culms 0.5–1 mm wide; spikelets loosely packed on rachis (7–9 per 5 mm); leaves 0.8–2.8(–3) mm wide
|[[Cyperus thyrsiflorus |Cyperus thyrsiflorus]]
|-id=key-1-111
|111
|Culms 2–2.6 mm wide; spikelets densely packed on rachis (11–21 per 5 mm); leaves (3–)4–5.8 mm wide
|[[Cyperus pseudothyrsiflorus|Cyperus pseudothyrsiflorus]]
|-id=key-1-112
|112
|Floral scales ascending, 1.7–2.5(–3.5) mm; achenes oblong-fusiform; rachilla wing thin, deciduous, narrow, less than 0.5 mm wide, covering less than 1/2 achene face
|[[#key-1-113| > 113]]
|-id=key-1-112
|112
|Floral scales appressed, mostly greater than 2.5 mm (rarely as short as 1.8 mm in C. retrorsus); achenes abruptly constricted, not fusiform; rachilla wing persistent, (0.2–)0.5–0.8 mm wide, covering at least 1/2 achene face
|[[#key-1-114| > 114]]
|-id=key-1-113
|113
|Floral scales stramineous; anthers 0.3–0.5 mm; achenes 1.2–1.5 mm; se United States
|[[Cyperus ovatus|Cyperus ovatus]]
|-id=key-1-113
|113
|Floral scales brick red; anthers (0.7–)1–1.5 mm; achenes 1.7–1.8 mm; coastal California
|[[Cyperus owanii|Cyperus owanii]]
|-id=key-1-114
|114
|Spikes dense or loose, ovoid; spikelets angular, with (1–)2–4(–6) floral scales; floral scales whitish with red speckles; foliage yellow-green
|[[Cyperus croceus|Cyperus croceus]]
|-id=key-1-114
|114
|Spikes dense, globose, oblong to oblong-cylindric; spikelets subterete (not angular), with 1–3(–5) floral scales; floral scales stramineous, brown, fuscous; foliage green
|[[#key-1-115| > 115]]
|-id=key-1-115
|115
|Spikes globose to globose-ovoid; spikelets (3.5–)4–7 mm; floral scales membranous, stramineous to brownish, often red-brown between ribs, 3.5–4.5 mm; achenes 1.5–2.3 mm; bracts ascending at 30(–45)°, adaxial surface scabridulous especially distally; plants single-stemmed or loosely cespitose
|[[Cyperus echinatus|Cyperus echinatus]]
|-id=key-1-115
|115
|Spikes oblong-ovoid, often with small basal branches; spikelets 2.2–4(–4.5) mm; floral scales nearly leathery, brown to stramineous or fuscous and lustrous, 1.8–2.5 mm; achenes 1.2–1.7 mm; bracts ascending at (30–)45°, scabridulous along margins, adaxial surface glabrous; plants densely cespitose
|[[Cyperus retrorsus|Cyperus retrorsus]]
|}
</div></div><!--

-->{{#Taxon:
name=Cyperus
|author=Gordon C. Tucker*;Brian G. Marcks*;J. Richard Carter *
|authority=Linnaeus
|rank=genus
|parent rank=family
|synonyms=
|basionyms=
|family=Cyperaceae
|illustrator=Yevonn Wilson-Ramsey
|illustration copyright=Flora of North America Association
|distribution=Pantemperate and tropical.
|reference=carter1984a;corcoran1941a;denton1978b;horvat1941a;marcks1972a;marcks1974a;mcgivney1938a;tucker1983a;tucker1993a;tucker1994a
|publication title=Sp. Pl.;Gen. Pl. ed.
|publication year=1753;1754
|special status=
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V23/V23_225.xml
|genus=Cyperus
}}<!--

-->[[Category:Treatment]][[Category:Cyperaceae]]