Cyperaceae

A large and difficult family, with 16 genera and 272 species in Michigan. Identification of all but the most distinctive species usually requires mature fruit. The floral structure is simple, with usually bisexual flowers subtended by a single scale (not two, the lemma and palea, as in grasses), and then arranged into spikelets of varied morphology. An exception is Scleria, where flowers are unisexual. In Carex, the flowers are also unisexual, but the female are enclosed in a sac, flask, bottle, or tube-shaped, often flattened, structure called the perigynium, this then subtended by a single bract. See Rothrock (2009) for a fine illustrated treatment of the non-Carex genera, with a focus on Indiana.

1. Achenes enclosed in a closed sac (perigynium) subtended by a scale, the style protruding through the apex; flowers strictly unisexual (sedges with exclusively male flowers should be keyed here).

Carex

1. Achenes not enclosed in a closed sac, naked beside the subtending scale; at least some flowers bisexual (except in Scleria).

2. Achenes white, hard (bone-like), ± spherical; flowers all unisexual.

Scleria

2. Achenes yellow, brown, or black, rarely whitish, not spherical; at least some flowers bisexual.

3. Scales of spikelets 2-ranked; spikelets ± flattened in cross-section and always more than one per inflorescence.

4. Stems usually ± angled, solid; inflorescences terminal; achenes without subtending bristles.

Cyperus

4. Stems round, hollow; inflorescences in the axils of stem leaves; achenes with subtending bristles.

Dulichium

3. Scales of spikelets spirally arranged (or if 2-ranked, the spikelet solitary); spikelets round or several-angled in cross-section, solitary or several to many per inflorescence.

5. Perianth bristles 6, 3 slender and 3 with an expanded, ± spongy, spoon-like portion at the tip.

Fuirena

5. Perianth bristles absent or 1 to many, all slender.

6. Spikelet or cluster of spikelets borne on one side of the stem at the base of a single ± erect to somewhat angled or curved involucral bract that appears to be a continuation of the stem.

7. Stems less than 0.5 mm thick; plants tiny, less than 10 cm tall.

Lipocarpha

7. Stems thicker than 0.5 mm; plants usually much taller than 10 cm.

8. Plants colonial from elongate rhizomes, perennial; usually more than 0.8 m tall (except in the submerged aquatic Schoenoplectus subterminalis); anthers 1–3.5 mm long.

Schoenoplectus

8. Plants cespitose, annual, less than 0.8 (–1) m tall; anthers 0.3–0.9 mm long.

Schoenoplectiella

6. Spikelet or spikelets terminating the stem or borne both terminally and laterally; if more than one spikelet, the inflorescence with (1–) 2 to several spreading to reflexed, leaf-like involucral bracts.

9. Spikelet solitary and terminal on the stem (very rarely a few smaller accessory spikelets occur at the base of the terminal spikelet in the bladeless genus Eleocharis).

10. Sheaths totally bladeless or at most with an apical tooth up to 1 mm long; achenes usually with an apical tubercle formed by the expanded and persistent base of the style.

Eleocharis

10. Upper sheaths with short green blades 0.3–12 cm long; achenes blunt at apex, tubercle absent.

11. Achenes subtended by conspicuous silky, white or tawny, hair-like bristles many times as long as the achenes.

12. Bristles numerous, ca. (12–) 15–50 or more; rhizomes erect, very short.

Eriophorum (in part)

12. Bristles 6; rhizomes horizontal and short-creeping.

Trichophorum alpinum

11. Achenes subtended by 1–8 bristles less than twice as long as the achenes, or bristles absent.

Trichophorum (in part)

9. Spikelets several to many on the stem, terminal or lateral.

13. Achenes subtended by (12–) 15–50 conspicuous, silky, white or tawny, hair-like bristles many times as long as the achenes.

Eriophorum (in part)

13. Achenes subtended by 1–8 bristles, or bristles absent.

14. Leaves flat or folded; with a definite, ± keeled midrib.

15. Achenes with a conspicuous tubercle formed by the expanded, persistent style base.

Rhynchospora (in part)

15. Achenes blunt at apex, without a tubercle; style base, if expanded, not persistent to maturity.

16. Widest leaves 4–15 mm wide; achenes subtended by 1–8 bristles.

17. Spikelets (10–) 15–36 mm long; achenes 3–5 mm long, including apiculus; anthers ca. (2.3–) 4–5 mm long; culms sharply 3-angled nearly or quite to the base; colonial from rhizomes with large corm-like thickenings.

Bolboschoenus

17. Spikelets 2–10 (–12) mm long, achenes 0.9–1.2 mm long; anthers 0.5–1.3 mm long; culms terete, obtusely 3-angled, or sharply 3-angled only toward summit; cespitose or with rhizomes lacking corm-like enlargements.

Scirpus

16. Widest leaves 0.5–3 mm wide; achenes lacking bristles.

Fimbristylis

14. Leaves inrolled and wiry; rounded on the back and without a definite midrib.

18. Styles 2-cleft; achenes subtended by slender bristles.

Rhynchospora (in part)

18. Styles 3-cleft; achenes lacking bristles.

19. Achenes 2.2–3.5 mm long; perennials 4–11 dm tall; colonial from elongated rhizomes.

Cladium

19. Achenes 0.7–0.8 mm long; tufted annuals 0.2–4 dm tall.

Bulbostylis

All species found in Cyperaceae

Bolboschoenus fluviatilisBULRUSH 
Bolboschoenus maritimusBULRUSH 
Bulbostylis capillarisSEDGE 
Carex acutiformisSEDGE 
Carex adustaSEDGE 
Carex aggregataSEDGE 
Carex alataWINGED SEDGE 
Carex albicansSEDGE 
Carex albolutescensGREENISH-WHITE SEDGE 
Carex albursinaSEDGE 
Carex alopecoideaSEDGE 
Carex amphibolaSEDGE 
Carex annectensSEDGE 
Carex aquatilisSEDGE 
Carex arctaSEDGE 
Carex arctataSEDGE 
Carex argyranthaSEDGE 
Carex assiniboinensisASSINIBOIA SEDGE 
Carex atherodesSEDGE 
Carex atlanticaSEDGE 
Carex atratiformisSEDGE 
Carex aureaSEDGE 
Carex backiiSEDGE 
Carex bebbiiSEDGE 
Carex bicknelliiSEDGE 
Carex billingsiiSEDGE 
Carex blandaSEDGE 
Carex breviorSEDGE 
Carex bromoidesSEDGE 
Carex brunnescensSEDGE 
Carex bushiiBUSH'S SEDGE 
Carex buxbaumiiSEDGE 
Carex canescensSEDGE 
Carex capillarisSEDGE 
Carex careyanaSEDGE 
Carex castaneaSEDGE 
Carex cephaloideaSEDGE 
Carex cephalophoraSEDGE 
Carex chordorrhizaSEDGE 
Carex communisSEDGE 
Carex comosaSEDGE 
Carex concinnaBEAUTY SEDGE 
Carex conjunctaSEDGE 
Carex conoideaBEAUTY SEDGE 
Carex craweiSEDGE 
Carex crawfordiiSEDGE 
Carex crinitaSEDGE 
Carex cristatellaSEDGE 
Carex crus-corviSEDGE 
Carex cryptolepisSEDGE 
Carex cumulataSEDGE 
Carex davisiiDAVIS' SEDGE 
Carex debilisSWAMP SEDGE 
Carex decompositaLOG SEDGE 
Carex deflexaSEDGE 
Carex deweyanaSEDGE 
Carex diandraSEDGE 
Carex digitalisSEDGE 
Carex dispermaSEDGE 
Carex duriusculaSEDGE 
Carex eburneaSEDGE 
Carex echinataSEDGE 
Carex echinodesSEDGE 
Carex emoryiSEDGE 
Carex exilisSEDGE 
Carex festucaceaFESCUE SEDGE 
Carex flaccaSEDGE 
Carex flavaSEDGE 
Carex foeneaSEDGE 
Carex folliculataSEDGE 
Carex formosaSEDGE 
Carex frankiiFRANK'S SEDGE 
Carex garberiSEDGE 
Carex gracilescensSEDGE 
Carex gracillimaSEDGE 
Carex granularisSEDGE 
Carex gravidaSEDGE 
Carex grayiSEDGE 
Carex griseaSEDGE 
Carex gynandraSEDGE 
Carex gynocratesSEDGE 
Carex haydeniiHAYDEN'S SEDGE 
Carex heleonastesSEDGE 
Carex hirsutellaSEDGE 
Carex hirtaSEDGE 
Carex hirtifoliaSEDGE 
Carex hitchcockianaSEDGE 
Carex houghtonianaSEDGE 
Carex hyalinolepisSEDGE 
Carex hystericinaSEDGE 
Carex inopsSEDGE 
Carex interiorSEDGE 
Carex intumescensSEDGE 
Carex jamesiiJAMES' SEDGE 
Carex lacustrisSEDGE 
Carex laevivaginataSEDGE 
Carex lasiocarpaSEDGE 
Carex laxiculmisSEDGE 
Carex laxifloraSEDGE 
Carex leavenworthiiSEDGE 
Carex lenticularisSEDGE 
Carex leptaleaSEDGE 
Carex leptonerviaSEDGE 
Carex limosaBOG SEDGE 
Carex lividaSEDGE 
Carex longiiSEDGE 
Carex lucorumSEDGE 
Carex lupuliformisSEDGE 
Carex lupulinaSEDGE 
Carex luridaSEDGE 
Carex magellanicaSEDGE 
Carex meadiiSEDGE 
Carex mediaSEDGE 
Carex merritt-fernaldiiSEDGE 
Carex mesochoreaSEDGE 
Carex michauxianaSEDGE 
Carex molestaSEDGE 
Carex muehlenbergiiSEDGE 
Carex muricataSEDGE 
Carex muskingumensisSEDGE 
Carex nigraBLACK SEDGE 
Carex normalisSEDGE 
Carex novae-angliaeNEW ENGLAND SEDGE 
Carex oligocarpaSEDGE 
Carex oligospermaSEDGE 
Carex ormostachyaSEDGE 
Carex pallescensPALE SEDGE 
Carex paucifloraSEDGE 
Carex peckiiSEDGE 
Carex pedunculataSEDGE 
Carex pellitaSEDGE 
Carex pensylvanicaSEDGE 
Carex plantagineaSEDGE 
Carex platyphyllaBROAD-LEAVED SEDGE 
Carex praegracilisSEDGE 
Carex praireaSEDGE 
Carex prasinaSEDGE 
Carex praticolaSEDGE 
Carex projectaSEDGE 
Carex pseudo-cyperusSEDGE 
Carex radiataSTRAIGHT-STYLED WOOD SEDGE 
Carex retroflexaSEDGE 
Carex retrorsaSEDGE 
Carex richardsoniiRICHARDSON'S SEDGE 
Carex roseaCURLY-STYLED WOOD SEDGE 
Carex rossiiROSS' SEDGE 
Carex rostrataSEDGE 
Carex sartwelliiSEDGE 
Carex scabrataSEDGE 
Carex schweinitziiSEDGE 
Carex scirpoideaBULRUSH SEDGE 
Carex scopariaSEDGE 
Carex seorsaSEDGE 
Carex siccataSEDGE 
Carex sparganioidesSEDGE 
Carex spicataSEDGE 
Carex sprengeliiSEDGE 
Carex squarrosaSEDGE 
Carex sterilisSEDGE 
Carex stipataSEDGE 
Carex stramineaSTRAW SEDGE 
Carex strictaSEDGE 
Carex suberectaSEDGE 
Carex swaniiSEDGE 
Carex sychnocephalaLONG-BEAKED SEDGE 
Carex sylvaticaSEDGE 
Carex teneraSEDGE 
Carex tenuifloraSEDGE 
Carex tetanicaSEDGE 
Carex texensisSEDGE 
Carex tinctaSEDGE 
Carex tonsaSEDGE 
Carex tribuloidesSEDGE 
Carex trichocarpaHAIRY-FRUITED SEDGE 
Carex trispermaSEDGE 
Carex tuckermaniiSEDGE 
Carex typhinaCAT-TAIL SEDGE 
Carex umbellataSEDGE 
Carex utriculataSEDGE 
Carex vaginataSEDGE 
Carex vesicariaSEDGE 
Carex virescensSEDGE 
Carex viridistellataSEDGE 
Carex viridulaSEDGE 
Carex vulpinoideaSEDGE 
Carex wiegandiiWIEGAND'S SEDGE 
Carex woodiiSEDGE 
Cladium mariscoidesTWIG-RUSH 
Cyperus acuminatusUMBRELLA SEDGE 
Cyperus bipartitusBROOK NUT SEDGE 
Cyperus diandrusUMBRELLA SEDGE 
Cyperus engelmanniiUMBRELLA SEDGE 
Cyperus erythrorhizosUMBRELLA SEDGE 
Cyperus esculentusYELLOW NUTSEDGE 
Cyperus flavescensYELLOW FLAT SEDGE 
Cyperus fuscusSEDGE 
Cyperus houghtoniiSMOOTH SAND SEDGE 
Cyperus iriaRICEFIELD FLATSEDGE 
Cyperus lupulinusSLENDER SAND SEDGE 
Cyperus odoratusUMBRELLA SEDGE 
Cyperus schweinitziiROUGH SAND SEDGE 
Cyperus squarrosusUMBRELLA SEDGE 
Cyperus strigosusLONG SCALED NUT SEDGE 
Dulichium arundinaceumTHREE-WAY SEDGE 
Eleocharis acicularisSPIKE-RUSH 
Eleocharis atropurpureaPURPLE SPIKE-RUSH 
Eleocharis compressaFLATTENED SPIKE RUSH 
Eleocharis ellipticaGOLDEN-SEEDED SPIKE RUSH 
Eleocharis engelmanniiENGELMANN'S SPIKE-RUSH 
Eleocharis equisetoidesHORSETAIL SPIKE RUSH 
Eleocharis erythropodaSPIKE-RUSH 
Eleocharis flavescensSPIKE-RUSH 
Eleocharis geniculataSPIKE-RUSH 
Eleocharis intermediaSPIKE-RUSH 
Eleocharis melanocarpaBLACK-FRUITED SPIKE-RUSH 
Eleocharis microcarpaSMALL-FRUITED SPIKE-RUSH 
Eleocharis nitidaSLENDER SPIKE-RUSH 
Eleocharis obtusaSPIKE-RUSH 
Eleocharis ovataSPIKE-RUSH 
Eleocharis palustrisSPIKE-RUSH 
Eleocharis parvulaDWARF SPIKE-RUSH 
Eleocharis quadrangulataFOUR-SIDED SPIKE-RUSH 
Eleocharis quinquefloraSPIKE-RUSH 
Eleocharis radicansSPIKE-RUSH 
Eleocharis robbinsiiSPIKE-RUSH 
Eleocharis rostellataSPIKE-RUSH 
Eleocharis tricostataTHREE-RIBBED SPIKE-RUSH 
Eriophorum angustifoliumNARROW-LEAVED COTTON-GRASS 
Eriophorum gracileSLENDER COTTON-GRASS 
Eriophorum tenellumCOTTON-GRASS 
Eriophorum vaginatumCOTTON-GRASS 
Eriophorum virginicumTAWNY COTTON-GRASS 
Eriophorum viridi-carinatumGREEN-KEELED COTTON-GRASS 
Fimbristylis autumnalisAUTUMN SEDGE 
Fimbristylis puberulaCHESTNUT SEDGE 
Fuirena pumilaUMBRELLA-GRASS 
Lipocarpha micranthaDWARF-BULRUSH 
Rhynchospora albaBEAK-RUSH 
Rhynchospora capillaceaBEAK-RUSH 
Rhynchospora capitellataBEAK-RUSH 
Rhynchospora fuscaBEAK-RUSH 
Rhynchospora macrostachyaTALL BEAK-RUSH 
Rhynchospora nitensSHORT-BEAKED BALD RUSH 
Rhynchospora recognitaGLOBE BEAK-RUSH 
Rhynchospora scirpoidesBALD-RUSH 
Schoenoplectiella halliiHALL'S BULRUSH 
Schoenoplectiella mucronataBOG BULRUSH 
Schoenoplectiella purshianaPURSH'S TUFTED BULRUSH 
Schoenoplectiella smithiiBULRUSH 
Schoenoplectus acutusHARDSTEM BULRUSH 
Schoenoplectus americanusOLNEY'S BULRUSH 
Schoenoplectus heterochaetusBULRUSH 
Schoenoplectus pungensTHREESQUARE 
Schoenoplectus subterminalisBULRUSH 
Schoenoplectus tabernaemontaniSOFTSTEM BULRUSH 
Schoenoplectus torreyiTORREY'S BULRUSH 
Scirpus atrocinctusWOOL-GRASS 
Scirpus atrovirensBULRUSH 
Scirpus cyperinusWOOL-GRASS 
Scirpus expansusBULRUSH 
Scirpus georgianusBULRUSH 
Scirpus hattorianusMOSQUITO BULRUSH 
Scirpus microcarpusBULRUSH 
Scirpus pedicellatusWOOL-GRASS 
Scirpus pendulusBULRUSH 
Scleria paucifloraFEW-FLOWERED NUT-RUSH 
Scleria reticularisNETTED NUT-RUSH 
Scleria triglomerataTALL NUT-RUSH 
Scleria verticillataNUT-RUSH 
Trichophorum alpinumBULRUSH 
Trichophorum cespitosumBULRUSH 
Trichophorum clintoniiCLINTON'S BULRUSH 

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. May 22, 2015. http://michiganflora.net/family.aspx?id=CYPERACEAE.