Cyperaceae

The Sedges (Cyperaceae) form a family of grass-like monocotyledonous plants, many of which are wind-pollinated.

Stems are usually roughly triangular in cross section, with no leaves above the base. The flower does not have a perianth or, if it does, it is very reduced to scales, bristles or hairs. The basic inflorescence is a spikelet similar to that of the grasses, which is why at one time they were believed to be the family most closely related to them, although now it is known that they are closer to the sedges. As with the rushes, the sedges can be confused with the grasses, but their leaves are tristic, they do not have a ligule and the sheaths are closed. Furthermore, the flowers of the grasses are enclosed by two bracts (the lemma and the palea) while those of the sedges are accompanied by a single bract. With a cosmopolitan distribution, they are found all over the world but preferably in temperate regions.

Description

Habit: Herbs, perennial or annual, rarely shrubs or lianas. When they are perennial herbs, they generally have a stem that is a rhizome, or stolon, or bulb, or a caudex carrying aerial culms that are often tussock. Stems more or less triangular in cross section, often without leaves above the base, with a solid pith.

Alternate, spiral, bifacial leaves, usually tristic (rarely distichous), with conical silica bodies, composed of sheath (sheathing leaves) and lamina; the sheath usually closed, the blade simple, undivided, with entire or minutely serrated margin, with parallel, linear, flattened, and thin venation. No stipules. With or without ligule. Lower leaves (and in some taxa all leaves) reduced to sheaths.

The inflorescence is a "sedges" spikelet, often above bracts, solitary or in a complex arrangement. The spikelets are bisexual or unisexual. Each spikelet consists of a central axis (the rachilla) carrying bracts with a spiral or distichous arrangement (also called scales or glumes), each of them (except sometimes the lower one) carrying a single flower.

Inconspicuous, small, hermaphroditic or unisexual flowers (if unisexual, the plant is monoecious), bracteate, actinomorphic, hypogynous.

Tepals absent or reduced to usually 3-6 (rarely 1 or numerous) separate scales, bristles, or hairs.

Androecium with 3 stamens (rarely 1 or 2, or more rarely 6 or more); separate filaments; non-sagitted anthers, with introrse and longitudinal dehiscence. The filaments elongate during anthesis.

Pollen usually unipore, released in pseudomonads (3 of the 4 microspores of the tetrad degenerate after microsporogenesis and become part of the pollen wall).

Gynoecium bicarpellate or tricarpellate (rarely 4 carpels), connate carpels, with the superior ovary, unilocular. The gynoecium of Carex and allies is surrounded by an inflated bract called the perigynium ("perigynium"), at the apex of the perigynium the style protrudes. Styles usually 2-3, elongated. Basal placentation, 1 ovule, anatropous, bitegmic, per ovary.

There are no nectaries.

The fruit is a nut (but also called achenes or abusively utricles), surrounded in some cases by persistent bristles of the perianth, lenticular or triangular in cross section.

Ecology

Cosmopolitan, especially represented in temperate regions. Usually, but not always, in humid environments. Carex is important in a wide number of ecosystems. Many sedges are dominant in ecosystems typical of humid soils.

Most are wind-pollinated, although insect pollination has appeared numerous times within the family, for example in Hypolytrum, and in some species of Ascolepis and Rhynchospora.

Fruit dispersal is often by water (due to the cork-textured fruit wall, or associated structures such as perianth bristles that trap air bubbles, for example in Cladium, Remirea, Eleocharis, Fuirena). External transport also occurs (by animals, without consuming it) through a hooked inflorescence axis, for example in Uncinia, or by muddy fruits that stick to the feathers or skin, for example in Fimbristylis. Transport by birds by imitation of the aril also occurs, for example in Scleria, and transport by wind, by action of elongated bristles, as in Eriophorum or in Scirpus. The perigonio of Carex often assists transport by water.

Phylogeny

The family has been recognized by modern classification systems such as the APG III classification system (2009) and the APWeb (2001 onwards), which place it in the order Poales of monocots. In turn, it is made up of more than 5,000 species, grouped into a hundred genera, being the third family of monocots in number of species. The genus Carex is especially diverse, with about 2000 species, important in a wide number of ecosystems. Despite its diversity, its economic importance is limited, although it is noteworthy that Cyperus papyrus is the species used to make papyrus in ancient Egypt.

Cyperaceae contain conical silica bodies unique to the family, distinguishing them from all other monocots. As with the Juncaceae, the Cyperaceae are often confused with grasses. They are distinguished from the latter by the more or less triangular stems, the tristic leaves, generally without ligules, and the closed sheaths. Cyperaceae flowers have a single bract or, as in Carex, a bract and a prophyll, whereas most grass flowers are associated with two bracts, the lemma and the palea.

The family is monophyletic (Muasya et al. 1998, Jones et al. 2007).

The family belongs to the sedge-sedge clade, along with Juncaceae and Thurniaceae. See Poales for a discussion of this clade.

In a morphological study of the family, Bruhl (1995) recognized two subfamilies and 10 tribes. The tribes represent groups that appear in phenetic and cladistic analyzes of the family, although only 4 of the 10 contain clear synapomorphies. Phylogenetic relationships were also established by a molecular DNA study of rbcL sequences (Muasya et al. 1998).

Combined analyzes of DNA and pollen data (Simpson et al. 2003) resolved a sister clade to the rest of the Cyperaceae, which corresponds to the Mapanioideae. Within it, two more clades have been resolved in the same way. One of them comprised taxa assigned to the tribe Hypolytreae, which had pollen of the Mapania type. The other comprised taxa primarily assigned to the tribe Chrysintricheae, and additionally included two genera of Hypolutreae, Capitularina and Exocarya. In this clade all taxa have pollen in pseudomonads.

Taxonomy

The family was recognized by the APG III (2009), the Linear APG III (2009) assigned it the family number 99. The family had already been recognized by the APG II (2003).

Cyperaceae is the third largest family of monocots, after Orchidaceae and Poaceae. It has 98 genera and about 5000 species. The most represented genera are Carex (2000 species, especially diverse), Cyperus (600 species), Fimbristylis (300 species), Scirpus (300 species), Rhynchospora (200 species), Scleria (200 species), and Eleocharis (200 species).

The list of genera, with their synonyms, according to the APWeb (visited January 2009):

• Abildgaardia Vahl = Fimbristylis Vahl
• Acorellus Palla = Cyperus L.
• Acriulus Ridl. = Scleria Bergius
• Actinoschoenus Benth.
• Actinoscirpus (Ohwi) R.W.Haines & Lye
• Afrotrilepis (Gilly) J.Raynal
• Alinula J.Raynal
• Amphiscirpus Oteng-Yeb.
• Androtrichum Brongn.
• Anosporum Nees = Cyperus L.
• Arthrostylis R.Br.
• Ascolepis Nees ex Steud.
• Ascopholis C.E.C.Fisch. = Cyperus L.
• Asterochaete Nees = Carpha Banks & Sol. ex R.Br.
• Baeothryon A.Dietr. = Eleocharis R.Br.
• Baumea Gaudich. = Machaerina Vahl
• Becquerelia Brongn.
• Bisboeckelera Kuntze
• Blepharolepis Nees = Scirpus L.
• Blysmocarex N.A.Ivanova = Kobresia Willd.
• Blysmopsis Oteng-Yeb. = Blysmus Panz. ex Schult.
• Blysmus Panz. ex Schult.
• Boeckeleria T.Durand = Tetraria P.Beauv.
• Bolboschoenus (Asch.) Palla
• Bulbostylis Kunth
• Calyptrocarya Nees
• Chapter J.V.Suringar = Capitularine Kern
• Capitularine Kern
• Carex L.
• Carpha Banks & Sol. ex R.Br.
• Catagyna Hutch. " Dalziel = Scleria Bergius
• Caustis R.Br.
• Cephalocarpus Nees
• Chaetocyperus Nees = Eleocharis R.Br.
• Chaetospora R.Br. = Schoenus L.
• Chamaegyne Suess. = Eleocharis R.Br.
• Chillania Roiv.
• Chlorocyperus Rikli = Cyperus L.
• Chondrachne R.Br. = Lepironia Rich.
• Chorizandra R.Br.
• Chrysitrix L.
• Cladium P.Browne
• Coleochloa Gilly
• Costular C.B.Clarke
• Courtoisia Nees (SUH) = Courtoisina Sojak
• Courtoisina Sojak
• Crossland W.Fitzg.
• Cryptangium Schrad. ex Nees = Lagenocarpus Nees
• Cryptopodium Schrad. ex Nees = Scleria Bergius
• Cyathochaeta Nees
• Cyathocoma Nees = Tetraria P.Beauv.
• Cymophyllus Mack. ex Britton & A.Br.
• Cyperus L.
• Desmoschoenus Hook.f.
• Said. P.Beauv. = Fimbristylis Vahl
• Dichromena Michx. = Rhynchospora Vahl
• Didymiandrum Gilly
• Diplacrum R.Br.
• Diplasia Pers.
• Diplocarex Hayata = Carex L.
• Dulichium Pers.
• Ecklonea Steud. = Trianoptiles Fenzl ex Endl.
• Egleria G.Eiten
• Eleocharis R.Br.
• Eleogiton Link (SUH) = Isolepis R.Br.
• Elyna Schrad. = Kobresia Willd.
• Elynanthus Nees = Tetraria P.Beauv.
• Epischoenus C.B.Clarke
• Eriophorella Holub = Trichophorum Pers.
• Eriophoropsis Palla = Eriophorum L.
• Eriophorum L.
• Erioscirpus Palla = Eriophorum L.
• Eriospora Hochst. ex A.Rich. = Coleochloa Gilly
• Evandra R.Br.
• Everardia Ridl.
• Exocarya Benth.
• Exochogyne C.B.Clarke
• Ficinia Schrad.
• Fimbristylis Vahl
• Fintelmannia Kunth = Trilepis Nees
• I was. Rottb.
• Gahnia J.R.Forst. " G.Forst.
• Galilee Parl. = Cyperus L.
• Gymnoschoenus Nees
• Heleocharis T.Lestib. = Eleocharis R.Br.
• Hellmuthia Steud.
• Helonema Suess. = Eleocharis R.Br.
• Hemicarex Benth. = Kobresia Willd.
• Hemicarpha Nees = Lipocarpha R.Br.
• Hemichlaena Schrad. = Ficinia Schrad.
• Holoschoenus Link (SUH) = Scirpoides Seg.
• Hoppia Nees = Bisboeckelera Kuntze
• Hymenochaeta P.Beauv. (SUH) = Actinoscirpus (Ohwi) R.W.Haines & Lye
• Hypolytrum Rich. ex Pers.
• Ideleria Kunth = Tetraria P.Beauv.
• Indocourtoisia Bennet " Raised (SUS) = Courtoisina Sojak
• Isolepis R.Br.
• Juncellus C.B.Clarke = Cyperus L.
• Kobresia Willd.
• Koyamaea W.W.Thomas & Davidse
• Kyllinga Rottb.
• Kyllingiella R.W.Haines & Lye
• Lagenocarpus Nees
• Lampocarya R.Br. = Gahnia J.R.Forst. " G.Forst.
• Lepidosperma Labill.
• Lepironia Rich.
• Lipocarpha R.Br.
• Lophocarpus Boeck. = Schoenus L.
• Lophoschoenus Stapf = Costular C.B.Clarke
• Machaerina Vahl
• Macrochaetium Steud. = Tetraria P.Beauv.
• Mapnia Aubl.
• Mapniopsis C.B.Clarke
• Mariscopsis Cherm. = Queenslandiella Domin
• Marisculus Goetgh. = Alinula J.Raynal
• Mariscus Vahl = Cyperus L.
• Maximoviczia A.P.Khokhr. (SUH) = Scirpus L.
• Maximovicziella A.P.Khokhr. = Scirpus L.
• Megarrhena Schrad. ex Nees = Androtrichum Brongn.
• Mesomelaena. Nees
• Microdracoids Hua
• Micropapyrus Suess. = Rhynchospora Vahl
• Morelotia Gaudich.
• Neesenbeckia Levyns
• Nelmesia Van der Veken
• Nemum Desv.
• Neo-Senea K.Schum. ex H.Pfeiff. = Lagenocarpus Nees
• Neolophocarpus E.G.Camus = Schoenus L.
• Oreobolopsis Koyama & Guagl.
• Oreobolus R.Br.
• Oreograstis K.Schum. = Carpha Banks & Sol. ex R.Br.
• Oxycaryum Nees
• Paramapania Uittien
• Pentasticha Turcz. = I was. Rottb.
• Phacellanthus Siebold & Zucc. (SUH) = Gahnia J.R.Forst. " G.Forst.
• Phylloscirpus C.B.Clarke
• Platylepis Kunth (SUH) = Ascolepis Nees ex Steud.
• Pleurostachys Brongn.
• Principality Uittien
• Pseudoeverardia Gilly = Everardia Ridl.
• Pseudomariscus Rauschert (SUS) = Courtoisina Sojak
• Pseudoschoenus (C.B.Clarke) Oteng-Yeb.
• Psilocarya Torr. = Rhynchospora Vahl
• Pteroscleria Nees = Diplacrum R.Br.
• Ptilanthelium Steud.
• Pycreus P.Beauv.
• Queenslandiella Domin
• Raynalia Sojak = Alinula J.Raynal
• Reedia F.Muell.
• Remirea Aubl.
• Rhynchocladium T.Koyama
• Rhynchospora Vahl
• Rikliella J.Raynal = Lipocarpha R.Br.
• Schoenodendron Engl. = Microdracoids Hua
• Schoenoides Seberg = Oreobolus R.Br.
• Schoenoplectus (Rchb.) Palla
• Schoenoxiphium Nees
• Schoenus L.
• Scirpidiella Rauschert = Isolepis R.Br.
• Scirpodendron Zipp. ex Kurz
• Scirpoides Seg.
• Scirpus L.
• Scleria Bergius
• Sickmannia Nees = Ficinia Schrad.
• Sorostachys Steud. = Cyperus L.
• Sphaerocyperus Lye
• Sphaeromariscus E.G.Camus = Cyperus L.
• Stenophyllus Raf. = Bulbostylis Kunth
• Sumatroscirpus Oteng-Yeb.
• Syntrinema H.Pfeiff. = Rhynchospora Vahl
• Tetraria P.Beauv.
• Tetrariopsis C.B.Clarke = Tetraria P.Beauv.
• Thoracostachyum Kurz = Mapnia Aubl.
• Torulinium Desv. = Cyperus L.
• Trachystylis S.T.Blake
• Trianoptiles Fenzl ex Endl.
• Trichophorum Pers.
• Trichoschoenus J.Raynal
• Tricostularia Nees ex Lehm.
• Trilepis Nees
• Tylocarya Nelmes = Fimbristylis Vahl
• Uncinia Pers.
• Vesicarex Steyerm. = Carex L.
• Vincentia Gaudich. = Machaerina Vahl
• Voladeria Benoist = Oreobolus R.Br.
• Volkiella Merxm. " Czech
• Websteria S.H.Wright

Economic importance

Economic importance is limited, with some species used for matting, thatching, weaving material, and writing material, many members are noxious weeds for agriculture, others provide food, fuel, and medicine, also material for construction, and for perfumery (Simpson and Inglis 2001).

The pith of Cyperus papyrus was used to make papyrus in ancient Egypt and this species is also often planted as an ornamental.

Others are also cultivated as ornamentals, for example Cyperus involucratus ("umbrella plant" or "umbrella plant" in English).

Cyperus rotundus is an agricultural weed.

Cyperus esculentus has edible underground storage organs ("chufas", in Spanish), which are used to make a refreshing drink called "horchata". They also have Mariscus umbellatus, Scirpus tuberosus, and Eleocharis dulcis, the latter being found in trade.

The stems and leaves of a few species of Cyperus, Carex, Eleocharis, Lepironia, and Scirpus provide tissue materials.

The roots of Cyperus longus and those of Cyperus articulatus have a sweet aroma and are used in perfumery.

The roots of Scirpus grossus and those of Scirpus articulatus are used in Indian medicine.

Various species of Carex are used as baling material, as hay or as straw.

Many members are important in conservation biology as dominant components of many wet ecosystems and are reliable indicators of habitat deterioration in those ecosystems.