The genera of Cyperaceae of Madagascar Author Rasaminirina, Fitiavana https://orcid.org/0000-0003-0162-7975 University of Antananarivo, Antananarivo, Madagascar Author Larridon, Isabel https://orcid.org/0000-0003-0285-722X Kew Madagascar Conservation Centre, Antananarivo, Madagascar & Royal Botanic Gardens, Kew, Richmond, UK i.larridon@kew.org text Plant Ecology and Evolution 2023 2023-08-29 156 3 276 310 http://dx.doi.org/10.5091/plecevo.98847 journal article http://dx.doi.org/10.5091/plecevo.98847 2032-3921-3-276 BC5E6BD70022518ABF185FC3C18147CE Rhynchospora Vahl (Vahl 1805: 229) nom. cons. Type species. Rhynchospora alba (L.) Vahl Description of the genus. Usually small to medium-sized perennials, rarely annuals; rhizomatous or with a poorly developed root system. Culms scapose or with 1-many nodes, rounded to trigonous. Leaves radical or radical and cauline; sheaths closed, ligule minute or absent. Involucral bracts leaf-like or reduced. Inflorescence very variable, paniculate, corymbose, anthelate or capitate, rarely pseudolateral. Glumes spirally arranged (rarely distichous), of increasing length to subequal, larger (1-)2-few glume(s) subtending a floret, enclosed by the wings of the next glume. Florets bisexual, the lowest few sterile and/or upper staminate (variable with species). Perianth bristles usually 3-6, or absent. Stamens (1-2-)3, inconspicuous. Style 2-fid, with base persistent (tubercle). Nutlets usually lenticular to globose. Embryo top-shaped in frontal view, root cap developed in a (sub)basal position, and first leaf primordium developed in a lateral position ( Carex -type embryo). Distribution and ecology. Rhynchospora is a cosmopolitan genus ( POWO 2022 ). It grows in seasonally wet to permanently flooded grassland, laterite outcrops, lake shores, stream sides, swamps, rice fields ( Browning and Goetghebeur 2017 ). Rhynchospora occurs throughout Madagascar; ten species are known including e.g. Rhynchospora holoschoenoides (Rich.) Herter (Fig. 11 ) and Rhynchospora angolensis Turrill (Fig. 12A ). Figure 11. Rhynchospora holoschoenoides . A - B . Habit. C . Leaf sheath. D . Leaf apex. E . Inflorescence. F . Head of spikelets. G - H . Spikelet, complete and opened to show florets. I . Glume, lateral view. J . Nutlet. A-D from Robinson 6123 ; E, G, I from Robinson 1048 ; F from Robinson 1456 ; J from Renvoize 5598 . Scale bars: A = 250 mm; B, E = 40 mm; C, F = 5 mm; G-I = 2 mm; D, J = 1 mm. Drawn by Jane Browning, reproduced with permission from the artist, originally published in Browning et al. (2020) .