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Family Cyperaceae

Description: Perennial or annual herbs, often with a grass-like or rush-like habit, tufted or rhizomatous, sometimes stoloniferous, rarely tuber-producing. Culms (aerial stems) usually solid, rarely hollow between transverse septa, triquetrous to terete, occasionally 4- or 5-angular.

Leaves only at base of the culm or also cauline, the outer basal ones often reduced to ± open sheathing scales in continuance of those on the rhizome; inner leaves, as well as the cauline ones, embracing the culm with closed tubular sheaths; blade usually narrow and grass-like, occasionally reduced; ligule present (membranous or ciliate) or absent.

Inflorescence simple or compound, variously umbel-like, panicle-like or head-like, or reduced to a single spikelet; subtended by one or more leaf-like or occasionally glume-like or culm-like involucral bracts, lowest ones often much exceeding inflorescence and resembling the leaves, the others gradually smaller, upper ones (and sometimes all) small and glume-like. Spikelets either solitary or clustered, terete or compressed, 1–many-flowered; rachilla sometimes winged. Flowers small and inconspicuous, bisexual, or unisexual and monoecious or very rarely dioecious, each usually solitary within a bract called a glume. Glumes arranged either distichously or spirally on the rachilla of the spikelet, one or more of the lower or upper ones often empty. Perianth reduced to hypogynous scales, bristles or hairs, very rarely subpetaloid or disk-like, often absent. Stamens 3 or fewer, very rarely more; filaments free; anthers basifixed, oblong or linear,2-locular, dehiscing by longitudinal slits, the connective often produced in a small apical appendage, glabrous or hispidulous. Ovary superior, 1-locular with one erect ovule; style terminal, filiform or variously thickened at the base, ± deeply divided into 2 or 3 (rarely more) branches, rarely simple.

Fruit a small seed-like nut, that from a 2-lobed style usually ± 2-sided and that from a 3-lobed style ± 3-angular or terete.

Photo Karen L Wilson

Photo J. & P. Edwards

Photo J. & P. Edwards

Photo J. & P. Edwards

Other photo
Photo Kristina Frank

Distribution and occurrence: World: c. 90 gen., c. 5,400 spp;, cosmopolitan, mostly in damp or swampy places. Aust.: c. 45 gen., c. 900 spp., all States. The genus Carex is one of the largest genera in the plant world, with about 2,200 species.

External links:
Angiosperm Phylogeny Website (Family: Cyperaceae, Order: Poales)

Most members of the family are of key ecological importance in a wide range of habitats globally. However, there are few species of economic importance in the commonly accepted sense. The tubers of some species of Cyperus and Eleocharis contain starch and have been used as food (e.g. Water chestnut, Eleocharis dulcis). The paper of the ancient Egyptians was manufactured from Papyrus (Cyperus papyrus L.). Some species are used regionally in the fabrication of mats, brooms, etc. A few have ornamental or medicinal purposes.

Note: leaves are described as septate-nodulose when they contain numerous small transverse septa that are obvious at least when dried.

Culm diameter and leaf breadth are measured about halfway along the organ. Culm length is measured from the base of the plant to the lowest involucral bract at base of inflorescence (in some cases, the inflorescence is very much longer than the true culm). Inflorescence length, where given, does not include any longer involucral bracts. Anther length measurements do not include any apical appendage because the appendages are fragile and break off readily.

The inflorescence in most members of the Cyperaceae has been called an anthela, but that name is technically inappropriate (see Wilson (1991) p. 367). The basic funnel-shaped structure, with spikelets on branches of different lengths is variously modified so that it appears umbel-like, panicle-like or even head-like to the casual glance. The inflorescence is here described as simple if there is only 1 order of branching present, compound if more. The spikelets are mostly easily recognizable units, with several–many modified bracts (glumes) each subtending a bisexual or unisexual flower or occasionally some empty at apex or base of spikelet. Generally, a rather leaf-like bract and a 2-keeled modified bract (prophyll) are present at the junction of the spikelet and inflorescence branch. In Carex, this arrangement is modified in female spikelets by the prophyll forming a fused 'flask' (utricle) around the 1-flowered spikelet. In subfamily Mapanioideae (here represented by Exocarya, Lepironia and Chorizandra), the floral arrangement is more complex and poorly understood. The basic floral unit in Exocarya and Lepironia consists of one broad, thick-textured, non-keeled, basal glume subtending 2 slender, thin-textured, lateral keeled glumes (with ciliolate keel) at each end of a 1 distichous, flattened array of 2–numerous slender, thin-textured, non-keeled glumes. The uppermost of these slender non-keeled glumes usually subtends a gynoecium, the rest with a single stamen or some empty. In Chorizandra, the floral unit differs in having a continuum of glume-form from the broader, mostly keeled (but not ciliolate) lowest 1–3 glumes to the narrow upper glumes. Also, the glumes are all spirally arranged, producing a terete unit. This floral unit is here termed a pseudospikelet since it may not be homologous with spikelets in the rest of the family. All floral scales are here called glumes. The pseudospikelets are clustered variously to form a spikelet-like (Lepironia) or head-like (Chorizandra) inflorescence or in spikelet-like units further clustered in compound umbel-like inflorescences (Exocarya).

**Trachystylis stradbrokensis (Domin) Kuek. occurs in SE Qld and may occur in coastal northeastern N.S.W.

Text by K. L. Wilson (1993; edited Aug 2013, June 2020)
Taxon concept:

Taxa not yet included in identification key

 Key to the genera 
1Spikelets with several–many flowers producing nuts, usually only 1 or 2 lowest glumes empty2
Spikelets or pseudospikelets with 1 or 2 (3) flowers producing nuts, usually several–many empty glumes at the base of the spikelet or pseudospikelet19
2Stems noded and leafy (also occasionally noded in aquatic species such as Isolepis fluitans, but then not large perennials, and bristles absent); hypogynous bristles or scales present3
Culms not noded; leaves all basal; hypogynous bristles or scales present or absent
                       Back to 1
3Three hypogynous scales inflated and more or less petaloid; 3 hair-like bristles also present; glumes with a long mucro about as long as glumeFuirena
All hypogynous bristles hair-like; glumes with a mucro no more than half glume length
                       Back to 2
4Spikelets less than 1 cm long; inflorescence branches scabrous; hypogynous bristles much longer than nutScirpus
Spikelets 1–2.5 cm long; inflorescence branches not scabrous; hypogynous bristles shorter than or equalling nut
                       Back to 3
5Style base enlarged and persistent on nut6
Style base enlarged or not, but not persistent on nut
                       Back to 2
6Inflorescence not subtended by leafy bracts; leaves reduced to sheaths, glabrous; hypogynous bristles usually presentEleocharis
Inflorescence subtended by leafy bracts; leaves with well-developed blade, hairy near mouth of sheath; hypogynous bristles always absent
                       Back to 5
7Hypogynous bristles presentSchoenoplectus
Hypogynous bristles absent
                       Back to 5
8Style base enlarged but not persistent9
Style base not enlarged or persistent
                       Back to 7
9Glumes spirally arranged and spikelets terete, or rarely distichous and spikelets compressed (but then inflorescence with numerous spikelets)Fimbristylis
Glumes distichous or upper part of spikelet twisted so as to be more or less spiral; spikelets compressed; inflorescence of 1–6 spikelets
                       Back to 8
10Style 2-fid11
Style 3-fid
                       Back to 8
11Glumes distichously arranged in spikelet. (Subgenus 4 Pycreus)Cyperus
Glumes spirally arranged in spikelet
                       Back to 10
12Involucral bracts glume-like or leaf-like, from shorter than inflorescence to twice as long as it (to 1.5 cm long); spikelets 2–8 mm longIsolepis
Involucral bracts culm-like, usually at least 4 times as long as inflorescence (to 25 cm long); spikelets 5–15 mm long
                       Back to 11
13Nutlet epidermal cells narrow and longitudinally elongated or oblong, with straight or slightly undulate anticlinal walls; nutlet surface smooth or transversely rugose; basal flowers sometimes presentSchoenoplectiella
Nutlet epidermal cells usually hexagonal or isodiametric in shape and with straight or slightly undulate anticlinal walls, or oblong and with heavily waving anticlinal walls; nutlet surface smooth; basal flowers absent
                       Back to 12
14Rachilla internodes thickened and clasping nut at maturity. (Subgenus 3 Torulinium)Cyperus
Rachilla neither thickened nor clasping nut
                       Back to
15Glumes distichously arranged in spikelet (spiral in Cyperus hamulosus but then plant has smell of fenugreek). (Subgenus 1 Anosporum, Subgenus 2 Cyperus)Cyperus
Glumes spirally arranged in spikelet, not smelling of fenugreek
                       Back to 14
16Nuts transversely wrinkled and/or stout perennials17
Nuts variously marked but never transversely wrinkled; small annuals or perennials
                       Back to 15
17Nutlet epidermal cells narrow and longitudinally elongated or oblong, with straight or slightly undulate anticlinal walls; nutlet surface smooth or transversely rugose; basal flowers sometimes presentSchoenoplectiella
Nutlet epidermal cells usually hexagonal or isodiametric in shape and with straight or slightly undulate anticlinal walls, or oblong and with heavily waving anticlinal walls; nutlet surface smooth; basal flowers absent
                       Back to 16
18Perennial with long-creeping, thick, woody rhizome to 1 cm diam.; minute hypogynous disc under nutFicinia
Plants in small tufts or with filiform rhizome; no disc under nut
                       Back to 16
19Female flowers enclosed in sac-like utricle20
Flowers not enclosed in a utricle
                       Back to 1
20Slender rachilla inside utricle with a stiff exserted hooked tip; inflorescence always a single spike (formerly genus Uncinia)Carex
No slender hooked rachilla inside the utricle; inflorescence of (1–) several–many spikes
                       Back to 19
21Female flowers apparently terminal, always only 1 per pseudospikelet (floral unit)22
Female or bisexual flowers lateral and axillary, one to many in a spikelet
                       Back to 19
22Leaves flat, leafy, usually present along the culms as well as at the base; involucral bracts flat, leafy; nut much longer than glumesExocarya
Leaves terete or reduced to sheaths, at base of culm only; involucral bracts terete but often broad and flattened at the base; nut shorter than to equalling glumes
                       Back to 21
23Nut biconvex; style 2-fid; inflorescence spike-like; nut finely striate longitudinally but not ribbedLepironia
Nut terete to obtusely trigonous, obovoid to globose; style (2- to) 3- or 4-fid; inflorescence globose, hemispherical, or ovoid; nut strongly ribbed longitudinally
                       Back to 22
24A hypogynous disk or 1 or 2 hyaline scales or 2–6 hypogynous bristles or scales present at base of nut (not always falling with nut)25
Hypogynous bristles, scales and disk absent
                       Back to 21
25Nut more or less enclosed in 2, or occasionally 1, hyaline scales. (Sect. Lipocarpha)Cyperus
Nut without hyaline scales
                       Back to 24
26Style simple or 2-fid27
Style 3–8-fid
                       Back to 25
27Style base differentiated, enlarged, and persistent; leaves without a liguleRhynchospora
Style base not differentiated or enlarged or persistent; leaves with a membranous ligule
                       Back to 26
28Hypogynous disk present at base of nut29
Hypogynous bristles or scales present at base of nut
                       Back to 26
29Glumes spirally arranged; most flowers bisexual; nut brownish, toughCladium
Glumes distichous; flowers unisexual; nut with white to purplish, fragile pericarp
                       Back to 28
30Upper internodes of rachilla prominently zigzagSchoenus
Upper internodes of rachilla straight
                       Back to 28
31Style base persistent, often enlarged in fruit32
Style base deciduous
                       Back to 30
32Inflorescence head-like33
Inflorescence panicle-like, umbel-like, or spike-like
                       Back to 31
33Ligule membranous, glabrous; inflorescence obconical or fan-shaped; leaf sheaths glabrousPtilothrix
Ligule membranous and ciliate; inflorescence globose; leaf sheaths long-ciliate on upper margins
                       Back to 32
34Bristles 6, as long as, or longer than, the nutCarpha
Bristles 2 to 5, much shorter than the nut
                       Back to 32
34Glumes spirally arranged in the spikelet; hypogynous scales inflated or thickenedLepidosperma
Glumes more or less distichously or spiro-distichously arranged in the spikelet; hypogynous scales flat, not thickened
                       Back to 32
35Robust perennials with inflorescence c. 40 cm long. (Gahnia erythrocarpa)Gahnia
Slender perennials with inflorescences 1–4[–30] cm long
                       Back to 34
35Hypogynous scales falling with the nut; leaf without pseudopetiole36
Hypogynous scales persistent on rachilla after nut falls; leaf with pseudopetiole
                       Back to 34
36Inflorescence condensed-compound and appearing head-like; rhizomes pseudobulbousChaetospora
Inflorescence open or, if reduced, not head-like; rhizomes not psuedobulbous
                       Back to 35
37Spikelets usually in clusters of 3, at 5–9 nodes; upper flower fertile; hypogynous scales 1/3–2/3 length of nutAnthelepis
Spikelets usually solitary, or 2 or 3 in a terminal cluster; upper flower reduced and sterile; hypogynous scales <1/5 length of nut
                       Back to 36
39Style simple or 2-fid40
Style 3–8-fid
                       Back to 24
40Style base enlarged, persistent; ligule absentRhynchospora
Style base enlarged or not, but not persistent
                       Back to 39
41Inflorescence umbel-like; ciliate ligule presentTrachystylis
Inflorescence of 1 to 3 dense, clustered heads; ligule absent
                       Back to 40
42Hyaline scales usually 2 enclosing nut, occasionally 1 or absent; apparent glumes (= spikelet bracts) flat with 0–2 nerves on each side of midrib; nut dorsiventrally compressed, trigonous or plano-convex. (Sect. Lipocarpha)Cyperus
Hyaline scales absent; glumes keeled, with 2–5 nerves on each side of midrib; nut laterally compressed (i.e. with an edge next to rachilla), biconvex. (Subgenus 5 Kyllinga)
                       Back to 41
43Upper internodes of rachilla zigzagSchoenus
Upper internodes of rachilla straight
                       Back to 39
44Annual; inflorescence of 1 to 3 clustered heads with numerous spikelets. (Sect. Lipocarpha)Cyperus
Perennials; inflorescence panicle-like, spike-like, or occasionally reduced to a few clustered spikelets
                       Back to 43
45Leaves reduced to blade no more than 1 cm long46
Leaves with well-developed blade to 1 m long
                       Back to 44
46Persistent style base not separated from body of nut by a constrictionMachaerina
Persistent style base separated from body of nut by a constriction
                       Back to 45
47Leaves without a liguleCaustis
Leaves with a ligule
                       Back to 46
48Leaves 2-ranked, isobilateralMachaerina
Leaves 3-ranked, dorsiventral
                       Back to 45
49Nut borne on inconspicuous hypogynous disk (disk may stay on rachilla rather than fall with nut)Cladium
Nut not borne on a hypogynous disk
                       Back to 48
50Spikelets disarticulating as a unit from axis at maturity. (Subgenus 2 Cyperus)Cyperus
Spikelets persistent, nuts falling separately from glumes at maturity
                       Back to 49
51Leaves with a liguleGahnia
Leaves without a ligule
                       Back to 50

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