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Paul Goetghebeur - One of the best experts on this subject based on the ideXlab platform.
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A new understanding of the giant genus Cyperus : impacts on African plant taxonomy
2020Co-Authors: Isabel Larridon, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Paul GoetghebeurAbstract:Recent systematic research of Cyperus s.l. (950 spp.) resulted in new insights towards a new classification reflecting natural relationships. Based on molecular phylogenetic data, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic with part of its species placed in segregate genera. Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well-resolved due to species radiation coinciding with evolution of C4 photosynthesis. Reconstructing relationships in the Cyperus clade is complicated by convergent evolution. Characters used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on current knowledge, the segregate genera had to be sunken into a broadened, monophyletic genus Cyperus. In Cyperus, two subgenera are recognised corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to previous segregate genera. Taxonomic changes were necessary to lump the segregates into Cyperus. Boundaries of many existing sections still need to be re-evaluated, in order that they become monophyletic. With the large diversity of Cyperus species found in Africa, African taxonomists are ideally situated to study its lower level systematics and ecology.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Recent plant systematic research of Cyperus and its related genera resulted in new insights. The goal is to obtain a classification of Cyperus s.l. reflecting natural relationships. Based on molecular phylogenetic research, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic since part of its species were placed in segregate genera. At the base, Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a single monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well resolved due to species radiation coinciding with the evolution of the C4 photosynthetic pathway. Reconstruction of evolutionary relationships in the Cyperus clade is not only complicated by species radiation, but also by convergent evolution of characters. We now know that characters previously used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on the current knowledge, we decided to lump the segregate genera into a broadened, monophyletic genus Cyperus. In the genus Cyperus, we now recognize two subgenera corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to the old segregate genera. We systematically re-evaluate the boundaries of the existing sections, in order that they become monophyletic taxa. As a consequence of lumping the segregate genera into Cyperus, all species from the segregate genera are now receiving a Cyperus name.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Originally, Cyperaceae species with flattened spikelets and distichous glumes were placed in the genus Cyperus. However, we now know that this morphology has independently evolved in other Cyperaceae genera, while reversal to spiral glumes has occurred in multiple Cyperus lineages. There has been disagreement whether to recognize Cyperus as a single large genus (c. 950 species) or to segregate it into c. 14 genera. Segregate genera in Cyperus s.l. have been delimited based on a single or a combination of characters, but molecular phylogenetic data demonstrated convergent evolution in several key characters. Using molecular phylogenetic data, we reconstructed a phylogenetic hypothesis of Cyperus s.l. The ancestor of Cyperus is a perennial with C3 photosynthesis, and spikelets with distichous glumes shedding individual fruits. Three segregate genera, differing by having spiral glumes (Kyllingiella, Oxycaryum) or spikelets dispersing as a single unit (Courtoisina), are derived from the C3 Cyperus s.s. ancestral morphology and were recently merged into Cyperus. A large (c. 760 species) monophyletic clade rapidly radiated from an ancestor, with an anthelate inflorescence and distichous glumes, which switched to C4 photosynthesis in the last 10 mya. Diversification has been accompanied by reductions leading to spikelets bearing single flowers (Alinula, Ascolepis, Lipocarpha, Volkiella), multiple origins of lateral nutlet orientation (Kyllinga, Pycreus, Queenslandiella), and evolution of sterile lower flowers (Remirea, SphaeroCyperus). To resolve the paraphyly of Cyperus and provide a classification reflecting evolution, we are revising generic delimitation, to recognize a single large genus Cyperus and delimit infrageneric taxa for clades supported by morphology.
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Radiations and paraphyly in Cyperus: challenging taxonomy of a giant genus
2020Co-Authors: Marc Reynders, Isabel Larridon, A. Muthama Muasya, Alexander Vrijdaghs, Wim Huygh, Paul GoetghebeurAbstract:Calibrated family level phylogenies of Cyperaceae, revealed several origins of C4 photosynthesis as a response to changing climatic conditions during the late Eocene (estimates between 15 and 10 mja) and seems to coincide with the origin of the savanna biome in Eastern Africa. The ecological advantages of C4 photosynthesis lead to a major radiative burst in Cyperus, resulting in a subclade of approximately 800 species (including 9 specialised, segregate genera). Eastern Africa can be identified as the original center of diversification of Cyperus C4, from there several smaller radiations occurred within other tropical regions. Unfortunately the fast mutation rates during this radiation result in poorly resolved phylogenies even when using fast mutating chloroplast and nuclear markers and AFLP. In contrast Cyperus C3 lineages are well resolved and form a grade at the base of the Cyperus phylogeny. Among the segregate genera, only Kyllinga is well supported as monophyletic. Lipocarpha and Ascolepis tend to be sister taxa, however, with various levels of support. In Pycreus one large clade is well supported, however, as sister group to Cyperus laevigatus a species with dorsiventrally flattened dimerous pistils (Pycreus has laterally flattened pistils). The other sections are nested within the Cyperus C4 polytomy as are the other (mostly monotypic) segregates. The presence of such a major hard polytomy, containing many convergent morphologies, forms an obstruction in building a modern classification for Cyperus. Two opposed classification strategies are possible. Following a cladistics method all segregate lineages are to be sunken into Cyperus. Due to the high morphological diversity among its lineages, Cyperus would then only be circumscribed by cladistics arguments. The other strategy is to maintain well supported segregate lineages on the generic level and circumscribe Cyperus s.s. as a paraphyletic entity, which reflects the evolutionary processes of the group. In deciding which strategy is be the most convenient for application on Cyperus, morphological characters which have been used for generic delimitations need to be reevaluated. Shifts in seed dispersal units from nutlets to complete spikelets, in glume placements from distichous back to spiral and from trimerous to dorsiventrally flattened dimerous pistils, have been proven to have occurred several different times throughout both Cyperus C3 and C4 and seem less feasible for generic delimitations. Laterally compressed dimerous pistils had been considered to be more reliable characteristics. However, broad ontogenetic and floral vascularization studies show reorganizations of the pistil occur relatively easy throughout Cyperoideae. Even the origin of specialised inflorescences as pseudospikelets seems to be convergent for several different lineages as Lipocarpha, Ascolepis, Alinula, Volckiella and Kyllinga among others.
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Cyperus albescens, a new combination in Cyperus (Cyperaceae) for the common (sub)tropical African and Asian species Lipocarpha chinensis
Kew Bulletin, 2016Co-Authors: Isabel Larridon, Kenneth Bauters, Rafaël Govaerts, Paul GoetghebeurAbstract:The replacement name Cyperus lipocarpha T. Koyama published in 1960 for Lipocarpha chinensis (Osbeck) J. Kern is incorrect, because an earlier epithet of a heterotypic name is available for combination in Cyperus. A new combination, Cyperus albescens (Steud.) Larridon & Govaerts is here proposed.
David A. Simpson - One of the best experts on this subject based on the ideXlab platform.
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A new understanding of the giant genus Cyperus : impacts on African plant taxonomy
2020Co-Authors: Isabel Larridon, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Paul GoetghebeurAbstract:Recent systematic research of Cyperus s.l. (950 spp.) resulted in new insights towards a new classification reflecting natural relationships. Based on molecular phylogenetic data, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic with part of its species placed in segregate genera. Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well-resolved due to species radiation coinciding with evolution of C4 photosynthesis. Reconstructing relationships in the Cyperus clade is complicated by convergent evolution. Characters used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on current knowledge, the segregate genera had to be sunken into a broadened, monophyletic genus Cyperus. In Cyperus, two subgenera are recognised corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to previous segregate genera. Taxonomic changes were necessary to lump the segregates into Cyperus. Boundaries of many existing sections still need to be re-evaluated, in order that they become monophyletic. With the large diversity of Cyperus species found in Africa, African taxonomists are ideally situated to study its lower level systematics and ecology.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Recent plant systematic research of Cyperus and its related genera resulted in new insights. The goal is to obtain a classification of Cyperus s.l. reflecting natural relationships. Based on molecular phylogenetic research, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic since part of its species were placed in segregate genera. At the base, Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a single monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well resolved due to species radiation coinciding with the evolution of the C4 photosynthetic pathway. Reconstruction of evolutionary relationships in the Cyperus clade is not only complicated by species radiation, but also by convergent evolution of characters. We now know that characters previously used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on the current knowledge, we decided to lump the segregate genera into a broadened, monophyletic genus Cyperus. In the genus Cyperus, we now recognize two subgenera corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to the old segregate genera. We systematically re-evaluate the boundaries of the existing sections, in order that they become monophyletic taxa. As a consequence of lumping the segregate genera into Cyperus, all species from the segregate genera are now receiving a Cyperus name.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Originally, Cyperaceae species with flattened spikelets and distichous glumes were placed in the genus Cyperus. However, we now know that this morphology has independently evolved in other Cyperaceae genera, while reversal to spiral glumes has occurred in multiple Cyperus lineages. There has been disagreement whether to recognize Cyperus as a single large genus (c. 950 species) or to segregate it into c. 14 genera. Segregate genera in Cyperus s.l. have been delimited based on a single or a combination of characters, but molecular phylogenetic data demonstrated convergent evolution in several key characters. Using molecular phylogenetic data, we reconstructed a phylogenetic hypothesis of Cyperus s.l. The ancestor of Cyperus is a perennial with C3 photosynthesis, and spikelets with distichous glumes shedding individual fruits. Three segregate genera, differing by having spiral glumes (Kyllingiella, Oxycaryum) or spikelets dispersing as a single unit (Courtoisina), are derived from the C3 Cyperus s.s. ancestral morphology and were recently merged into Cyperus. A large (c. 760 species) monophyletic clade rapidly radiated from an ancestor, with an anthelate inflorescence and distichous glumes, which switched to C4 photosynthesis in the last 10 mya. Diversification has been accompanied by reductions leading to spikelets bearing single flowers (Alinula, Ascolepis, Lipocarpha, Volkiella), multiple origins of lateral nutlet orientation (Kyllinga, Pycreus, Queenslandiella), and evolution of sterile lower flowers (Remirea, SphaeroCyperus). To resolve the paraphyly of Cyperus and provide a classification reflecting evolution, we are revising generic delimitation, to recognize a single large genus Cyperus and delimit infrageneric taxa for clades supported by morphology.
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towards a new classification of the giant paraphyletic genus Cyperus cyperaceae phylogenetic relationships and generic delimitation in c4 Cyperus
Botanical Journal of the Linnean Society, 2013Co-Authors: Isabel Larridon, Marc Reynders, Kenneth Bauters, David A. Simpson, Wim Huygh, Muthama A Muasya, Paul GoetghebeurAbstract: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
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The status of Cyperus pertenuis and Cyperus scariosus (Cyperaceae)
Kew Bulletin, 2012Co-Authors: V. P. Prasad, David A. SimpsonAbstract:Cyperus pertenuis Roxb. is re-instated as a separate species based on specimens previously assigned to C. scariosus. The distribution range of C. scariosus is redefined. The typification of both species is clarified.
Isabel Larridon - One of the best experts on this subject based on the ideXlab platform.
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A new understanding of the giant genus Cyperus : impacts on African plant taxonomy
2020Co-Authors: Isabel Larridon, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Paul GoetghebeurAbstract:Recent systematic research of Cyperus s.l. (950 spp.) resulted in new insights towards a new classification reflecting natural relationships. Based on molecular phylogenetic data, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic with part of its species placed in segregate genera. Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well-resolved due to species radiation coinciding with evolution of C4 photosynthesis. Reconstructing relationships in the Cyperus clade is complicated by convergent evolution. Characters used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on current knowledge, the segregate genera had to be sunken into a broadened, monophyletic genus Cyperus. In Cyperus, two subgenera are recognised corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to previous segregate genera. Taxonomic changes were necessary to lump the segregates into Cyperus. Boundaries of many existing sections still need to be re-evaluated, in order that they become monophyletic. With the large diversity of Cyperus species found in Africa, African taxonomists are ideally situated to study its lower level systematics and ecology.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Recent plant systematic research of Cyperus and its related genera resulted in new insights. The goal is to obtain a classification of Cyperus s.l. reflecting natural relationships. Based on molecular phylogenetic research, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic since part of its species were placed in segregate genera. At the base, Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a single monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well resolved due to species radiation coinciding with the evolution of the C4 photosynthetic pathway. Reconstruction of evolutionary relationships in the Cyperus clade is not only complicated by species radiation, but also by convergent evolution of characters. We now know that characters previously used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on the current knowledge, we decided to lump the segregate genera into a broadened, monophyletic genus Cyperus. In the genus Cyperus, we now recognize two subgenera corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to the old segregate genera. We systematically re-evaluate the boundaries of the existing sections, in order that they become monophyletic taxa. As a consequence of lumping the segregate genera into Cyperus, all species from the segregate genera are now receiving a Cyperus name.
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Exploring giant genera and their satellites: tales from the C3 Cyperus universe
2020Co-Authors: Isabel LarridonAbstract:Cyperaceae (or sedges) form the third largest plant family of the monocots with ca. 5400 species and 106 genera. Cyperaceae did not only evolve into a large diversity of genera and species in the tropics and subtropics, but they are also often dominantly present in the vegetation of temperate and arctic regions. Sedges contribute significantly to the botanical diversity of wetlands. The Cyperus clade (Cyperoideae, Cypereae) includes ca. 950 species of grass-like plants with complex inflorescences. Species of the Cyperus clade either use C3 photosynthesis (linked with eucyperoid anatomy) (C3 Cyperus), or C4 photosynthesis (linked with chlorocyperoid anatomy) (C4 Cyperus). This PhD project focusses C3 Cyperus. The aim is to create a detailed molecular phylogenetic hypothesis of C3 Cyperus in order to establish (1) how C3 Cyperus relates to C4 Cyperus, and (2) how the different C3 Cyperus taxa relate to one another. In this study, both nuclear ribosomal (ETS1f) and plastid (rpl32-trnL and trnH-psbA) DNA markers are used to create a molecular phylogenetic hypothesis. Molecular phylogenetic data are combined with carbon isotope analysis (D13C), morphology, embryography, floral and spikelet ontogeny, anatomy and biogeography. In our opinion, the Cyperus clade includes two genera Androtrichum and Cyperus (s.l.). C3 Cyperus forms a grade at the basis of Cyperus (C3 photosynthesis is the plesiomorphic state for the Cyperus clade), in which a well-supported monophyletic clade is nested encompassing the C4 Cyperus species. C3 Cyperus (ca. 190 spp.) is less species rich and less diverse than C4 Cyperus (ca. 760 spp.). The small genera Courtoisina and Oxycaryum are included in C3 Cyperus as new sections, which also contain Cyperus s.s. species with intermediate morphologies. The small genus Kyllingiella is included in the existing C3 Cyperus section Leucocephali. These taxa were previously recognised at generic level due to specific characteristics which differentiate them from Cyperus s.s. The currently recognised sections in C3 Cyperus are generally well-supported in the molecular phylogeny, however, ‘Cyperus sect. Glutinosi’ and ‘C. sect. Dichostylis’ sensu Kukenthal are heterogeneous as they include both C3 and C4 species. We aim to provide a revision and a preliminary new classification of C3 Cyperus with clearly characterised monophyletic groups.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Originally, Cyperaceae species with flattened spikelets and distichous glumes were placed in the genus Cyperus. However, we now know that this morphology has independently evolved in other Cyperaceae genera, while reversal to spiral glumes has occurred in multiple Cyperus lineages. There has been disagreement whether to recognize Cyperus as a single large genus (c. 950 species) or to segregate it into c. 14 genera. Segregate genera in Cyperus s.l. have been delimited based on a single or a combination of characters, but molecular phylogenetic data demonstrated convergent evolution in several key characters. Using molecular phylogenetic data, we reconstructed a phylogenetic hypothesis of Cyperus s.l. The ancestor of Cyperus is a perennial with C3 photosynthesis, and spikelets with distichous glumes shedding individual fruits. Three segregate genera, differing by having spiral glumes (Kyllingiella, Oxycaryum) or spikelets dispersing as a single unit (Courtoisina), are derived from the C3 Cyperus s.s. ancestral morphology and were recently merged into Cyperus. A large (c. 760 species) monophyletic clade rapidly radiated from an ancestor, with an anthelate inflorescence and distichous glumes, which switched to C4 photosynthesis in the last 10 mya. Diversification has been accompanied by reductions leading to spikelets bearing single flowers (Alinula, Ascolepis, Lipocarpha, Volkiella), multiple origins of lateral nutlet orientation (Kyllinga, Pycreus, Queenslandiella), and evolution of sterile lower flowers (Remirea, SphaeroCyperus). To resolve the paraphyly of Cyperus and provide a classification reflecting evolution, we are revising generic delimitation, to recognize a single large genus Cyperus and delimit infrageneric taxa for clades supported by morphology.
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Radiations and paraphyly in Cyperus: challenging taxonomy of a giant genus
2020Co-Authors: Marc Reynders, Isabel Larridon, A. Muthama Muasya, Alexander Vrijdaghs, Wim Huygh, Paul GoetghebeurAbstract:Calibrated family level phylogenies of Cyperaceae, revealed several origins of C4 photosynthesis as a response to changing climatic conditions during the late Eocene (estimates between 15 and 10 mja) and seems to coincide with the origin of the savanna biome in Eastern Africa. The ecological advantages of C4 photosynthesis lead to a major radiative burst in Cyperus, resulting in a subclade of approximately 800 species (including 9 specialised, segregate genera). Eastern Africa can be identified as the original center of diversification of Cyperus C4, from there several smaller radiations occurred within other tropical regions. Unfortunately the fast mutation rates during this radiation result in poorly resolved phylogenies even when using fast mutating chloroplast and nuclear markers and AFLP. In contrast Cyperus C3 lineages are well resolved and form a grade at the base of the Cyperus phylogeny. Among the segregate genera, only Kyllinga is well supported as monophyletic. Lipocarpha and Ascolepis tend to be sister taxa, however, with various levels of support. In Pycreus one large clade is well supported, however, as sister group to Cyperus laevigatus a species with dorsiventrally flattened dimerous pistils (Pycreus has laterally flattened pistils). The other sections are nested within the Cyperus C4 polytomy as are the other (mostly monotypic) segregates. The presence of such a major hard polytomy, containing many convergent morphologies, forms an obstruction in building a modern classification for Cyperus. Two opposed classification strategies are possible. Following a cladistics method all segregate lineages are to be sunken into Cyperus. Due to the high morphological diversity among its lineages, Cyperus would then only be circumscribed by cladistics arguments. The other strategy is to maintain well supported segregate lineages on the generic level and circumscribe Cyperus s.s. as a paraphyletic entity, which reflects the evolutionary processes of the group. In deciding which strategy is be the most convenient for application on Cyperus, morphological characters which have been used for generic delimitations need to be reevaluated. Shifts in seed dispersal units from nutlets to complete spikelets, in glume placements from distichous back to spiral and from trimerous to dorsiventrally flattened dimerous pistils, have been proven to have occurred several different times throughout both Cyperus C3 and C4 and seem less feasible for generic delimitations. Laterally compressed dimerous pistils had been considered to be more reliable characteristics. However, broad ontogenetic and floral vascularization studies show reorganizations of the pistil occur relatively easy throughout Cyperoideae. Even the origin of specialised inflorescences as pseudospikelets seems to be convergent for several different lineages as Lipocarpha, Ascolepis, Alinula, Volckiella and Kyllinga among others.
Marc Reynders - One of the best experts on this subject based on the ideXlab platform.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Recent plant systematic research of Cyperus and its related genera resulted in new insights. The goal is to obtain a classification of Cyperus s.l. reflecting natural relationships. Based on molecular phylogenetic research, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic since part of its species were placed in segregate genera. At the base, Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a single monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well resolved due to species radiation coinciding with the evolution of the C4 photosynthetic pathway. Reconstruction of evolutionary relationships in the Cyperus clade is not only complicated by species radiation, but also by convergent evolution of characters. We now know that characters previously used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on the current knowledge, we decided to lump the segregate genera into a broadened, monophyletic genus Cyperus. In the genus Cyperus, we now recognize two subgenera corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to the old segregate genera. We systematically re-evaluate the boundaries of the existing sections, in order that they become monophyletic taxa. As a consequence of lumping the segregate genera into Cyperus, all species from the segregate genera are now receiving a Cyperus name.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Originally, Cyperaceae species with flattened spikelets and distichous glumes were placed in the genus Cyperus. However, we now know that this morphology has independently evolved in other Cyperaceae genera, while reversal to spiral glumes has occurred in multiple Cyperus lineages. There has been disagreement whether to recognize Cyperus as a single large genus (c. 950 species) or to segregate it into c. 14 genera. Segregate genera in Cyperus s.l. have been delimited based on a single or a combination of characters, but molecular phylogenetic data demonstrated convergent evolution in several key characters. Using molecular phylogenetic data, we reconstructed a phylogenetic hypothesis of Cyperus s.l. The ancestor of Cyperus is a perennial with C3 photosynthesis, and spikelets with distichous glumes shedding individual fruits. Three segregate genera, differing by having spiral glumes (Kyllingiella, Oxycaryum) or spikelets dispersing as a single unit (Courtoisina), are derived from the C3 Cyperus s.s. ancestral morphology and were recently merged into Cyperus. A large (c. 760 species) monophyletic clade rapidly radiated from an ancestor, with an anthelate inflorescence and distichous glumes, which switched to C4 photosynthesis in the last 10 mya. Diversification has been accompanied by reductions leading to spikelets bearing single flowers (Alinula, Ascolepis, Lipocarpha, Volkiella), multiple origins of lateral nutlet orientation (Kyllinga, Pycreus, Queenslandiella), and evolution of sterile lower flowers (Remirea, SphaeroCyperus). To resolve the paraphyly of Cyperus and provide a classification reflecting evolution, we are revising generic delimitation, to recognize a single large genus Cyperus and delimit infrageneric taxa for clades supported by morphology.
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Radiations and paraphyly in Cyperus: challenging taxonomy of a giant genus
2020Co-Authors: Marc Reynders, Isabel Larridon, A. Muthama Muasya, Alexander Vrijdaghs, Wim Huygh, Paul GoetghebeurAbstract:Calibrated family level phylogenies of Cyperaceae, revealed several origins of C4 photosynthesis as a response to changing climatic conditions during the late Eocene (estimates between 15 and 10 mja) and seems to coincide with the origin of the savanna biome in Eastern Africa. The ecological advantages of C4 photosynthesis lead to a major radiative burst in Cyperus, resulting in a subclade of approximately 800 species (including 9 specialised, segregate genera). Eastern Africa can be identified as the original center of diversification of Cyperus C4, from there several smaller radiations occurred within other tropical regions. Unfortunately the fast mutation rates during this radiation result in poorly resolved phylogenies even when using fast mutating chloroplast and nuclear markers and AFLP. In contrast Cyperus C3 lineages are well resolved and form a grade at the base of the Cyperus phylogeny. Among the segregate genera, only Kyllinga is well supported as monophyletic. Lipocarpha and Ascolepis tend to be sister taxa, however, with various levels of support. In Pycreus one large clade is well supported, however, as sister group to Cyperus laevigatus a species with dorsiventrally flattened dimerous pistils (Pycreus has laterally flattened pistils). The other sections are nested within the Cyperus C4 polytomy as are the other (mostly monotypic) segregates. The presence of such a major hard polytomy, containing many convergent morphologies, forms an obstruction in building a modern classification for Cyperus. Two opposed classification strategies are possible. Following a cladistics method all segregate lineages are to be sunken into Cyperus. Due to the high morphological diversity among its lineages, Cyperus would then only be circumscribed by cladistics arguments. The other strategy is to maintain well supported segregate lineages on the generic level and circumscribe Cyperus s.s. as a paraphyletic entity, which reflects the evolutionary processes of the group. In deciding which strategy is be the most convenient for application on Cyperus, morphological characters which have been used for generic delimitations need to be reevaluated. Shifts in seed dispersal units from nutlets to complete spikelets, in glume placements from distichous back to spiral and from trimerous to dorsiventrally flattened dimerous pistils, have been proven to have occurred several different times throughout both Cyperus C3 and C4 and seem less feasible for generic delimitations. Laterally compressed dimerous pistils had been considered to be more reliable characteristics. However, broad ontogenetic and floral vascularization studies show reorganizations of the pistil occur relatively easy throughout Cyperoideae. Even the origin of specialised inflorescences as pseudospikelets seems to be convergent for several different lineages as Lipocarpha, Ascolepis, Alinula, Volckiella and Kyllinga among others.
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Three new combinations in African Cyperus (Cyperaceae)
Plant Ecology and Evolution, 2019Co-Authors: Isabel Larridon, Marc ReyndersAbstract:Background – During the past decade several molecular phylogenetic studies tackled the complex relationships within tribe Cypereae. Based on these studies, previously accepted segregate genera such as Pycreus were sunk into the genus Cyperus. Recently, while revising the West African species of Cyperus, three taxa previously placed in Pycreus were identified for which a name in Cyperus is lacking. Methods – The taxonomic changes are performed according to the International Code of Nomenclature for algae, fungi, and plants. Results – Three new combinations in Cyperus are made for names currently placed in Pycreus.
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Taxonomic changes in C 4 Cyperus (Cypereae, Cyperoideae, Cyperaceae): combining the sedge genera Ascolepis , Kyllinga and Pycreus into Cyperus s.l.
Phytotaxa, 2014Co-Authors: Isabel Larridon, Marc Reynders, Kenneth Bauters, Wim Huygh, Paul GoetghebeurAbstract:The sedge genera Alinula , Ascolepis , Kyllinga , Lipocarpha , Pycreus , Queenslandiella , Remirea , SphaeroCyperus and Volkiella (Cyperaceae) were recognised at generic level because they possess specialised inflorescence and/or flower characters. However, recent molecular phylogenetic analyses show that these genera are all nested in a paraphyletic Cyperus s.s. and therefore should be viewed as part of a broadly circumscribed genus Cyperus . For all species of Alinula and for the single species of Queenslandiella , Remirea and SphaeroCyperus , Cyperus names were already published by other authors. For the species of Lipocarpha and Volkiella , Cyperus names and a new sectional classification are published in a separate paper including a detailed molecular phylogenetic hypothesis for these taxa. Based on a study of herbarium specimens and literature, in this paper, twenty species of Ascolepis , seventeen species of Kyllinga , and six species of Pycreus , which do not yet have a validly published and legitimate name in Cyperus , are formally included into Cyperus as new combinations or new names. Notes on the synonymy of an African Pycreus species are also included.
Wim Huygh - One of the best experts on this subject based on the ideXlab platform.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Recent plant systematic research of Cyperus and its related genera resulted in new insights. The goal is to obtain a classification of Cyperus s.l. reflecting natural relationships. Based on molecular phylogenetic research, Cyperus s.l. is monophyletic (= the Cyperus clade), but Cyperus s.s. is paraphyletic since part of its species were placed in segregate genera. At the base, Cyperus s.l. species using C3 photosynthesis form a paraphyletic grade (= C3 Cyperus). All C4 Cyperus s.l. species form a single monophyletic clade (= C4 Cyperus) nested in C3 Cyperus. While relationships in C3 Cyperus are clear, some relationships in C4 Cyperus are not well resolved due to species radiation coinciding with the evolution of the C4 photosynthetic pathway. Reconstruction of evolutionary relationships in the Cyperus clade is not only complicated by species radiation, but also by convergent evolution of characters. We now know that characters previously used for generic delimitation originated multiple times independently (e.g. spiral glumes, single-flowered spikelets and laterally flattened nutlets). Based on the current knowledge, we decided to lump the segregate genera into a broadened, monophyletic genus Cyperus. In the genus Cyperus, we now recognize two subgenera corresponding to C3 Cyperus and C4 Cyperus. Within these subgenera sections are placed, some of which correspond to the old segregate genera. We systematically re-evaluate the boundaries of the existing sections, in order that they become monophyletic taxa. As a consequence of lumping the segregate genera into Cyperus, all species from the segregate genera are now receiving a Cyperus name.
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Tackling convergent evolution, radiation and paraphyly: towards a modern classification of the giant genus Cyperus
2020Co-Authors: Isabel Larridon, Marc Reynders, A. Muthama Muasya, Alexander Vrijdaghs, Kenneth Bauters, David A. Simpson, Wim Huygh, Paul GoetghebeurAbstract:Originally, Cyperaceae species with flattened spikelets and distichous glumes were placed in the genus Cyperus. However, we now know that this morphology has independently evolved in other Cyperaceae genera, while reversal to spiral glumes has occurred in multiple Cyperus lineages. There has been disagreement whether to recognize Cyperus as a single large genus (c. 950 species) or to segregate it into c. 14 genera. Segregate genera in Cyperus s.l. have been delimited based on a single or a combination of characters, but molecular phylogenetic data demonstrated convergent evolution in several key characters. Using molecular phylogenetic data, we reconstructed a phylogenetic hypothesis of Cyperus s.l. The ancestor of Cyperus is a perennial with C3 photosynthesis, and spikelets with distichous glumes shedding individual fruits. Three segregate genera, differing by having spiral glumes (Kyllingiella, Oxycaryum) or spikelets dispersing as a single unit (Courtoisina), are derived from the C3 Cyperus s.s. ancestral morphology and were recently merged into Cyperus. A large (c. 760 species) monophyletic clade rapidly radiated from an ancestor, with an anthelate inflorescence and distichous glumes, which switched to C4 photosynthesis in the last 10 mya. Diversification has been accompanied by reductions leading to spikelets bearing single flowers (Alinula, Ascolepis, Lipocarpha, Volkiella), multiple origins of lateral nutlet orientation (Kyllinga, Pycreus, Queenslandiella), and evolution of sterile lower flowers (Remirea, SphaeroCyperus). To resolve the paraphyly of Cyperus and provide a classification reflecting evolution, we are revising generic delimitation, to recognize a single large genus Cyperus and delimit infrageneric taxa for clades supported by morphology.
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Radiations and paraphyly in Cyperus: challenging taxonomy of a giant genus
2020Co-Authors: Marc Reynders, Isabel Larridon, A. Muthama Muasya, Alexander Vrijdaghs, Wim Huygh, Paul GoetghebeurAbstract:Calibrated family level phylogenies of Cyperaceae, revealed several origins of C4 photosynthesis as a response to changing climatic conditions during the late Eocene (estimates between 15 and 10 mja) and seems to coincide with the origin of the savanna biome in Eastern Africa. The ecological advantages of C4 photosynthesis lead to a major radiative burst in Cyperus, resulting in a subclade of approximately 800 species (including 9 specialised, segregate genera). Eastern Africa can be identified as the original center of diversification of Cyperus C4, from there several smaller radiations occurred within other tropical regions. Unfortunately the fast mutation rates during this radiation result in poorly resolved phylogenies even when using fast mutating chloroplast and nuclear markers and AFLP. In contrast Cyperus C3 lineages are well resolved and form a grade at the base of the Cyperus phylogeny. Among the segregate genera, only Kyllinga is well supported as monophyletic. Lipocarpha and Ascolepis tend to be sister taxa, however, with various levels of support. In Pycreus one large clade is well supported, however, as sister group to Cyperus laevigatus a species with dorsiventrally flattened dimerous pistils (Pycreus has laterally flattened pistils). The other sections are nested within the Cyperus C4 polytomy as are the other (mostly monotypic) segregates. The presence of such a major hard polytomy, containing many convergent morphologies, forms an obstruction in building a modern classification for Cyperus. Two opposed classification strategies are possible. Following a cladistics method all segregate lineages are to be sunken into Cyperus. Due to the high morphological diversity among its lineages, Cyperus would then only be circumscribed by cladistics arguments. The other strategy is to maintain well supported segregate lineages on the generic level and circumscribe Cyperus s.s. as a paraphyletic entity, which reflects the evolutionary processes of the group. In deciding which strategy is be the most convenient for application on Cyperus, morphological characters which have been used for generic delimitations need to be reevaluated. Shifts in seed dispersal units from nutlets to complete spikelets, in glume placements from distichous back to spiral and from trimerous to dorsiventrally flattened dimerous pistils, have been proven to have occurred several different times throughout both Cyperus C3 and C4 and seem less feasible for generic delimitations. Laterally compressed dimerous pistils had been considered to be more reliable characteristics. However, broad ontogenetic and floral vascularization studies show reorganizations of the pistil occur relatively easy throughout Cyperoideae. Even the origin of specialised inflorescences as pseudospikelets seems to be convergent for several different lineages as Lipocarpha, Ascolepis, Alinula, Volckiella and Kyllinga among others.
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Taxonomic changes in C 4 Cyperus (Cypereae, Cyperoideae, Cyperaceae): combining the sedge genera Ascolepis , Kyllinga and Pycreus into Cyperus s.l.
Phytotaxa, 2014Co-Authors: Isabel Larridon, Marc Reynders, Kenneth Bauters, Wim Huygh, Paul GoetghebeurAbstract:The sedge genera Alinula , Ascolepis , Kyllinga , Lipocarpha , Pycreus , Queenslandiella , Remirea , SphaeroCyperus and Volkiella (Cyperaceae) were recognised at generic level because they possess specialised inflorescence and/or flower characters. However, recent molecular phylogenetic analyses show that these genera are all nested in a paraphyletic Cyperus s.s. and therefore should be viewed as part of a broadly circumscribed genus Cyperus . For all species of Alinula and for the single species of Queenslandiella , Remirea and SphaeroCyperus , Cyperus names were already published by other authors. For the species of Lipocarpha and Volkiella , Cyperus names and a new sectional classification are published in a separate paper including a detailed molecular phylogenetic hypothesis for these taxa. Based on a study of herbarium specimens and literature, in this paper, twenty species of Ascolepis , seventeen species of Kyllinga , and six species of Pycreus , which do not yet have a validly published and legitimate name in Cyperus , are formally included into Cyperus as new combinations or new names. Notes on the synonymy of an African Pycreus species are also included.
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towards a new classification of the giant paraphyletic genus Cyperus cyperaceae phylogenetic relationships and generic delimitation in c4 Cyperus
Botanical Journal of the Linnean Society, 2013Co-Authors: Isabel Larridon, Marc Reynders, Kenneth Bauters, David A. Simpson, Wim Huygh, Muthama A Muasya, Paul GoetghebeurAbstract: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