Affinities in C3 Cyperus lineages (Cyperaceae) revealed using molecular phylogenetic data and carbon isotope analysis

Maximum likelihood and Bayesian analyses of nrDNA (ETS1f) and plastid DNA (rpl32-trnL, trnH-psbA) sequence data are presented for 'C-3 Cyperus' (Cyperaceae). The term 'C-3 Cyperus' indicates all species of Cyperus s.l. that use C-3 photosynthesis linked with eucyperoid vegetative anatomy. Sampling comprises 77 specimens of 61 different taxa, representing nearly all previously recognized subdivisions of C-3 Cyperus and the segregate genera Courtoisina, Kyllingiella and Oxycaryum. According to our results, the Cyperus clade is divided in six well-supported clades. The first of these clades (clade 1) forms three subclades largely corresponding to Cyperus sections Haspani, Incurvi and Diffusi. Clade 2 comprises the entirely New World C. section Luzuloidei sensu Denton (1978). Clade 3 is a highly diverse clade including two subclades: clade 3a, C. sections Pseudanosporum and Anosporum plus the segregate genera Courtoisina and Oxycaryum; and clade 3b, C. section Fusci. Clade 4 corresponds to C. section Alternifolii and clade 5 to C. section Leucocephali plus the segregate genus Kyllingiella. The sixth clade is a well-supported monophyletic clade encompassing all C-4 Cyperus s.l. species ('C-4 Cyperus'). This study establishes a phylogenetic framework for future studies. (C) 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167, 19-46.