CYPERACEAE 莎草科 suo cao ke Dai Lunkai (戴伦凯)1, Liang Songyun (梁松筠 Liang Song-jun)1, Zhang Shuren (张树仁)1, Tang Yancheng (汤彦承 Tang Yen-cheng)1; Tetsuo Koyama2, Gordon C. Tucker3, David A. Simpson4, Henry J. Noltie5, Mark T. Strong6, Jeremy J. Bruhl7, Karen L. Wilson8, A. Muthama Muasya9 Herbs, annual or perennial, rhizomatous to stoloniferous. Culms (stems) simple, often 3-sided. Leaves basal and/or cauline, often 3-ranked, comprising a blade and sheath but sometimes only sheath present; sheath open or closed; ligule often present, some- times on opposite side to leaf blade; leaf blade usually linear, grasslike, sometimes basally broader and constricted into a pseudopeti- ole. Involucral bracts 1 to several, leaflike or glumelike. Inflorescences unbranched and spicate or capitate, to branched and anthelate (umbel-like) or paniculate, comprising 1 to many ultimate inflorescence units, these either indeterminate and called spikelets or in a few genera determinate and called pseudospikelets (see explanation below). Spikelets with 1 to many glumes, sometimes reduced to a single flower and aggregated into unisexual spikes; glumes membranous to leathery, spirally arranged or 2-ranked, each subtending a single flower. Pseudospikelets comprising 2–12 membranous scalelike floral bracts on a much reduced axis; lowest 2 bracts oppo- site, keeled, pseudospikelet subtended and usually hidden by a glumelike bract; bracts spirally arranged and aggregated into spike- letlike spikes. Flowers bisexual or unisexual with plants monoecious or rarely dioecious. Perianth absent or reduced to bristles or scales. Stamens 1–3; anthers basifixed. Ovary 2- or 3-carpellate, unilocular, with a single ovule; style divided or rarely undivided, base sometimes persistent and variously shaped in fruit; stigmas 2 or 3. Fruit usually a hard 2- or 3-sided nutlet, rarely with a suc- culent or corky exocarp, surface smooth or variously minutely patterned, sometimes partially or completely enclosed by an enlarged basal prophyll (utricle). One hundred and six genera and ca. 5,400 species: worldwide except Antarctica; 33 genera and 865 species (326 endemic, five introduced) in China. Recent phylogenetic studies (e.g., D. A. Simpson et al., Aliso 23: 72–83. 2007; A. M. Muasya et al., Bot. Rev. (Lancaster) 75: 52–66. 2009) suggest that tribal and generic delimitation in Cyperaceae is likely to be modified in the future. The closest relatives to Cyperaceae are Juncaceae and Thurniaceae (D. A. Simpson in P. Rudall, P. J. Cribb, D. F. Cutler & C. J. Humphries, eds., Monocot. Syst. Evol. 2: 497–509. 1995) in the order Poales. Poaceae, which shares some characteristics of Cyperaceae, such as wind pollination and reduced floral structure, has often been placed near to Cyperaceae but is now shown to be more distantly related (H. P. Linder & E. A. Kellogg in P. Rudall et al., loc. cit.: 473–496; D. A. Simpson in P. Rudall et al., loc. cit.: 497–509). Inflorescence structure in Cyperaceae is notoriously difficult to interpret due to its highly reduced nature. Consequently, the terminology used in describing parts of the inflorescence can be confusing with several terms often being applied to the same structure. In addition, several terms are also used in the Poaceae, but they do not always relate to the same structure in both families. A laudable attempt to standardize terminology in Cyperaceae was made by I. Kukkonen (Ann. Bot. Fenn. 31: 37–43. 1994). In our treatment we have attempted to keep terminology as simple as possible. Inflorescences are generally either unbranched or very shortly branched and spicate or capitate in appearance to prominently branched and paniculate or anthelate (umbel-like), with variations around these. The basic unit of the inflorescence in most Cyperaceae is the spikelet. This com- prises a very short to elongated axis, which subtends one to many scalelike bracts, referred to here as glumes. Each glume subtends and partially hides a single very small, bisexual or unisexual flower, which may or may not have a perianth. The perianth, when present, is reduced to bristles or scales. There may be 1–3 stamens and a pistil comprising an ovary, style, and 2 or 3 stigmas. The ovary gives rise to a hard, 1-seeded nutlet (sometimes referred to as an achene). Spikelets tend to be aggregated into larger structures known as spikes. In the tribe Cariceae this basic structure is modified such that the spikelet is reduced to a single flower that is enclosed by a saclike structure known as a utricle, the latter being a modified prophyll at the base of the spikelet. The utricle is subtended by a glumelike bract, and the whole structure is again aggregated with others into spikes. Some confusion arises with caricoid spikes especially as the spikelets comprise only one flower and are subtended by a glumelike bract. This has meant that spikes are sometimes referred to as spikelets and the glumelike bracts as true glumes. The spikelet is indeterminate, i.e., having no terminal flower. However, in Hypolytrum, Lepironia, and Mapania, the basic inflorescence unit has an apparently terminal female flower. To distinguish this type of unit, the term pseudospikelet is used here; some authors refer to it as a spicoid. Its structure is rather different to that of the spikelet, comprising 2–12 scalelike floral bracts on a very much reduced axis. The two lowest bracts are opposite, keeled, and often enclose the upper bracts (when the latter are present). The lower bracts subtend a male flower comprising a single stamen, the upper bracts usually being empty. The terminal flower, which is not subtended by a floral bract, is female. There are no perianth bristles or scales, and the whole structure is subtended and partially to fully hidden by a glumelike bract. These are again aggregated into spikes, but there is further 1 Herbarium, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing 100093, People’s Republic of China. 2 Kochi Prefectural Makino Botanical Garden and Museum, 4200-6 Godaisan, Kochi City 781-8125, Japan; Department of Natural Sciences, Bishop Museum, 1525 Bernice Street, Honolulu, Hawaii 96817-2704, U.S.A. 3 Department of Biological Sciences, Eastern Illinois University, 600 Lincoln Avenue, Charleston, Illinois 61920-3099, U.S.A. 4 Herbarium, Library, Art and Archives, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, United Kingdom. 5 Herbarium, Royal Botanic Garden Edinburgh, 20a Inverleith Row, Edinburgh EH3 5LR, United Kingdom. 6 United States National Herbarium, Department of Botany, National Museum of Natural History, MRC-166, Smithsonian Institution, P.O. Box 37012, Washington, DC 20013-7012, U.S.A. 7 Department of Botany, School of Environmental and Rural Science, University of New England, Armidale, New South Wales 2351, Australia. 8 National Herbarium of New South Wales, Royal Botanic Gardens Sydney, Mrs Macquaries Road, Sydney, New South Wales 2000, Australia. 9 Department of Botany, University of Cape Town, Private Bag X3, Rondebosch 7701, South Africa. 164 CYPERACEAE 165 confusion in terminology with the spikes sometimes being referred to as spikelets. The above interpretation of the pseudospikelet is widely accepted, although some workers have interpreted it as a single flower. One of us (Dai) believes that if Kyllinga and Pycreus are treated as separate genera from Cyperus, as they are in this treatment, then Juncellus and Mariscus should also be separated from Cyperus on account of their distinct morphological characters. Tang Tsin & Wang Fa-Tsuan. 1961. Cyperaceae (1). In: Tang Tsin & Wang Fa-Tsuan, eds., Fl. Reipubl. Popularis Sin. 11: i–xv, 1–261; Liang Song-yun, Dai Lun-kai, Tang Yan-cheng & Li Pei-chun. 2000. Cyperaceae (2). In: Dai Lun-kai & Liang Song-yun, eds., Fl. Reipubl. Popularis Sin. 12: i–xxii, 1–582. Glossary Within the definitions, italics indicate terms that are defined in this glossary. Amphicarpous – applied to a small secondary inflorescence occurring Paniculate – inflorescence comprising partial inflorescences arising at at the base of the culm in certain genera, particularly intervals along the main inflorescence axis. Schoenoplectus. Partial inflorescence – primary branches of an inflorescence. Androgynous – having male and female flowers in the same structure Perianth bristles – small bristlelike or scalelike structures at the base of such as a spike in Carex. the nutlet. Presumed to be the remnants of a fully developed Anthela (plural anthelae, adjective anthelate) – an umbel-like perianth. inflorescence in which the primary branches ± arise from the same Prophyll – 2-keeled structure at the base of a branch within an point, the inflorescence being subtended by 1 to several involucral inflorescence. It may be glumelike or tubular or, in Kobresia and bracts. Carex, developed into a utricle. Beak – short extension at the apex of a utricle or nutlet. Pseudospikelet – the ultimate inflorescence unit in Hypolytrum, Biconvex – 2-sided, the sides convex. Lepironia, and Mapania. Has a much reduced axis and appears Cancellate – having the appearance of a lattice. flowerlike. Comprises 2–12 scalelike bracts each subtending a male flower. The whole structure is terminated by a female flower, thus Capitate – headlike inflorescence, without any apparent branching. making it determinate. Cladoprophyll – a sterile utricle found at the base of a Carex spike. Rachis – the axis of a spike. Compound – applied to an inflorescence or partial inflorescence where Rachilla – the axis of a spikelet. there are 2 orders of branching, i.e., primary and secondary. Ray – branches of an anthela. Compressed trigonous – 3-sided, but distinctly flattened and thus appearing to be 2-sided. Rhizome – underground stem, which may be short, often giving the plant a tufted habit, or long creeping. Conic – cone-shaped, being wider at the base than the apex; here it is used as the 3-dimensional equivalent of lanceolate. Scalelike bract – membranous scalelike structure in a pseudospikelet each of which subtends a male flower comprising a single stamen Contraligule – membranous, ligulelike structure at the apex of the leaf only.