The megadiverse genus Carex (c. 2000 species, Cyperaceae) has a nearly cosmopolitan distribution, displaying an inverted latitudinal richness gradient with higher species diversity in cold‐temperate areas of the Northern Hemisphere. Despite great expansion in our knowledge of the phylogenetic history of the genus and many molecular studies focusing on the biogeography of particular groups during the last few decades, a global analysis of Carex biogeography and diversification is still lacking. For this purpose, we built the hitherto most comprehensive Carex‐dated phylogeny based on three markers (ETS–ITS–matK), using a previous phylogenomic Hyb‐Seq framework, and a sampling of two‐thirds of its species and all recognized sections. Ancestral area reconstruction, biogeographic stochastic mapping, and diversification rate analyses were conducted to elucidate macroevolutionary biogeographic and diversification patterns. Our results reveal that Carex originated in the late Eocene in E Asia, where it probably remained until the synchronous diversification of its main subgeneric lineages during the late Oligocene. E Asia is supported as the cradle of Carex diversification, as well as a “museum” of extant species diversity. Subsequent “out‐of‐Asia” colonization patterns feature multiple asymmetric dispersals clustered toward present times among the Northern Hemisphere regions, with major regions acting both as source and sink (especially Asia and North America), as well as several independent colonization events of the Southern Hemisphere. We detected 13 notable diversification rate shifts during the last 10 My, including remarkable radiations in North America and New Zealand, which occurred concurrently with the late Neogene global cooling, which suggests that diversification involved the colonization of new areas and expansion into novel areas of niche space.
be merged for downstream analyses. Moreover, our study contributes to the growing consensus that targeted sequencing data are a powerful tool in resolving rapid radiations.
Maximum likelihood and Bayesian analyses of nrDNA (ETS1f) and plastid DNA (rpl32‐trnL, trnH‐psbA) sequence data are presented for ‘C3Cyperus’ (Cyperaceae). The term ‘C3Cyperus’ indicates all species of Cyperus s.l. that use C3 photosynthesis linked with eucyperoid vegetative anatomy. Sampling comprises 77 specimens of 61 different taxa, representing nearly all previously recognized subdivisions of C3Cyperus 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 C4Cyperus s.l. species (‘C4Cyperus’). This study establishes a phylogenetic framework for future studies. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167, 19–46.
Phylogenetic studies of Carex L. (Cyperaceae) have consistently demonstrated that most subgenera and sections are para-or polyphyletic. Yet, taxonomists continue to use subgenera and sections in Carex classification. Why? The Global Carex Group (GCG) here takes the position that the historical and continued use of subgenera and sections serves to (i) organize our understanding of lineages in Carex, (ii) create an identification mechanism to break the~2000 species of Carex into manageable groups and stimulate its study, and (iii) provide a
The field of systematics is experiencing a new molecular revolution driven by the increased availability of high-throughput sequencing technologies. As these techniques become more affordable, the increased genomic resources have increasingly far-reaching implications for our understanding of the Tree of Life. With c. 2000 species, Carex (Cyperaceae) is one of the five largest genera of angiosperms and one of the two largest among monocots, but the phylogenetic relationships between the main lineages are still poorly understood. We designed a Cyperaceae-specific HybSeq bait kit using transcriptomic data of Carex siderosticta and Cyperus papyrus. We identified 554 low-copy nuclear orthologous loci, targeting a total length of c. 1 Mbp. Our Cyperaceae-specific kit shared loci with a recently published angiosperm-specific Anchored Hybrid Enrichment kit, which enabled us to include and compile data from different sources. We used our Cyperaceae kit to sequence 88 Carex spp., including samples of all the five major clades in the genus. For the first time, we present a phylogenetic tree of Carex based on hundreds of loci (308 nuclear exon matrices, 543 nuclear intron matrices and 66 plastid exon matrices), demonstrating that there are six strongly supported main lineages in Carex: the Siderostictae, Schoenoxiphium, Unispicate, Uncinia, Vignea and Core Carex clades. Based on our results, we suggest a revised subgeneric treatment and provide lists of the species belonging to each of the subgenera. Our results will inform future biogeographic, taxonomic, molecular dating and evolutionary studies in Carex and provide the step towards a revised classification that seems likely to stand the test of time.
Maximum likelihood and Bayesian inference analyses of nuclear ribosomal DNA (ETS1f) and plastid DNA (rpl32‐trnL, trnH‐psbA) sequence data are presented for ‘C4 Cyperus’ (Cyperaceae). The term ‘C4 Cyperus’ encompasses all species of Cyperus s.l. that use C4 photosynthesis linked with chlorocyperoid vegetative anatomy. Sampling comprises 107 specimens of 104 different taxa, including many of the subdivisions of C4 Cyperus s.s. and all C4 segregate genera (Alinula, Ascolepis, Kyllinga, Lipocarpha, Pycreus, Queenslandiella, Remirea, Sphaerocyperus and Volkiella). According to our results, C4 Cyperus is a well‐supported monophyletic clade nested in C3 Cyperus. Despite the lack of resolution along the backbone of the C4 Cyperus clade and for some internal branches, several well‐supported clades can be distinguished. The first clade in C4 Cyperus is formed by Cyperus cuspidatus and C. waterloti. Other recognizable and well‐supported clades correspond to segregate genera, i.e. Ascolepis, Lipocarpha including Volkiella, and Kyllinga. Species of C4 Cyperus s.s. form a core grade in which the C4 segregate genera are embedded. Pycreus, the largest segregate genus composed of c. 120 species, is not monophyletic as it includes several C4 species of Cyperus s.s. This study establishes a phylogenetic framework for revising the classification and character evolution in Cyperus s.l. © 2013 The Linnean Society of London
Background and aims -Recent molecular studies validate a broad definition of Cyperus (Cyperaceae) uniting genera previously scattered in Cyperoideae. First indication of their affinity with Cyperus was obtained through embryography. Cyperus consists of a paraphyletic C 3 Cyperus and monophyletic C 4 Cyperus. In this study, we aim to check and clarify the putative positions of the segregate genera in C 3 Cyperus. Additional information is given and remarks are made on the position of some as yet unplaced species or sections in the C 3 Cyperus phylogeny. Methods -Embryos of Cyperus constanzae and C. gardneri were cleared and drawn. Inflorescences of selected C 3 Cyperus species were investigated using scanning electron and light microscopy. Histochemical tests were performed to assess the presence of suberin in the 'corky' tissue of the nutlets of Cyperus pectinatus. Key results -Embryography not only supports tribal classification in Cyperoideae, it is also phylogenetically informative in C 3 Cyperus. Morphology and ontogeny support molecular phylogenetic results suggesting the inclusion of the segregate genera in C 3 Cyperus as new sections or in established sections, and confirm the need to broaden the circumscription of some of these sections. Conclusion -Although less diverse than C 4 Cyperus, C 3 Cyperus includes clades which evolved an exceptional morphological diversity compared to its limited species numbers. The segregate genera Courtoisina (deciduous spikelets), Kyllingiella (spirally-arranged glumes) and Oxycaryum (spirallyarranged glumes and dorsiventrally flattened dimerous gynoecia), and the taxon Anosporum (recognised at sectional, subgeneric or generic level) are here included in C 3 Cyperus (= Cyperus subg. Anosporum) as sections or included in an existing section (Kyllingiella is included in Cyperus sect. Leucocephali). A formal taxonomic revision is presented with relevant new names and combinations, synonyms, diagnoses and identification keys.
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