Latest Articles from Plant Ecology and Evolution Latest 3 Articles from Plant Ecology and Evolution https://plecevo.eu/ Fri, 29 Mar 2024 09:34:17 +0200 Pensoft FeedCreator https://plecevo.eu/i/logo.jpg Latest Articles from Plant Ecology and Evolution https://plecevo.eu/ The genera of Cyperaceae of Madagascar https://plecevo.eu/article/98847/ Plant Ecology and Evolution 156(3): 276-310

DOI: 10.5091/plecevo.98847

Authors: Fitiavana Rasaminirina, Isabel Larridon

Abstract: Background and aims – The rise of DNA sequencing in systematics has brought more understanding of the Cyperaceae family worldwide. Through these studies, it has been possible to delineate major clades and classify its species into subfamilies, tribes, and genera. Today, we have a good understanding of the species diversity and geographic distribution of the genera. However, in the case of Madagascar, the only complete taxonomic treatment of Cyperaceae dates from 1937. Although recent monographs exist for some genera in Madagascar, the taxonomic treatment of the Cyperaceae of Madagascar has not been updated until now. Hence, the present work aims to produce an updated treatment at the generic level including descriptions and an identification key of all Cyperaceae genera in Madagascar. Material and methods – Books and scientific articles containing descriptions of the genera of Cyperaceae of Madagascar, and information on their ecology and distribution were consulted, as well as herbarium specimens, collections, and data available from online herbaria and aggregator portals. Key results – Madagascar is very rich in Cyperaceae. The species of the Cyperaceae family on the island are distributed in 24 genera, including one endemic genus, i.e. Trichoschoenus. Ten genera are monotypic on the island. Sixteen of the 29 genera described in the Flore de Madagascar remain accepted but the others are now either synonyms of Cyperus, or no longer apply because they are absent from Madagascar, such as Scirpus. Regarding their habitat and ecology, some genera are specific to a particular habitat, like Costularia, while others that are very broadly distributed, like Cyperus and Scleria. Conclusion – Our study provides an updated overview of the genera of Cyperaceae of Madagascar, including an identification key, descriptions, and illustrations.

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Research Article Tue, 29 Aug 2023 11:16:00 +0300
Reassessment of morphological species delimitations in the Cyperus margaritaceus-niveus complex using morphometrics https://plecevo.eu/article/97453/ Plant Ecology and Evolution 156(1): 112-127

DOI: 10.5091/plecevo.97453

Authors: Martin Xanthos, Simon J. Mayo, Isabel Larridon

Abstract: Background and aims – The Cyperus margaritaceus-niveus complex is a group of ten tropical species from sub-Saharan Africa and Madagascar: C. karlschumannii, C. kibweanus, C. ledermannii, C. margaritaceus, C. niveus, C. nduru, C. obtusiflorus, C. somaliensis, C. sphaerocephalus, and C. tisserantii. They are characterised by a capitate head of white-yellow spikelets and modified culm bases and recent molecular analysis puts them in a distinct clade. The group lacks a modern taxonomic revision, and the taxa described in the Flora treatments of the past 50 years differ considerably in their circumscription. In this study, morphometric analyses are used to test species limits to establish more stable morphological delimitations of the taxa. Material and methods – An examination of 15 morphological characters on 489 herbarium specimens was carried out and the data was analysed using Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA) with cross-validation, and Classification and Regression Tree (CART) analysis. Cyperus kibweanus was not further considered due to lack of material. Key results – Both PCA and LDA showed varying degrees of overlap in the nine remaining taxa, with no single group clearly separating in multivariate space. However, cross-validation clearly showed C. margaritaceus as a distinct entity despite its overwhelming presence in the PCA. Both LDA and CART failed to separate C. niveus as a distinct group as its specimens were dispersed among the other groups. Differing results were obtained for other taxa depending on the type of analysis. Cyperus margaritaceus, C. nduru, and C. sphaerocephalus were divided into two groups by CART but re-examination of the specimens does not definitively support the idea that these infraspecific groups represent separate taxa. Conclusions – The results show that eight morphospecies are recognised by LDA and six morphospecies by CART. Characters used to separate the taxa in Flora treatments scored high loadings in the analysis showing their high taxonomic utility value. The methods used can be applied to resolving other complexes in the Cyperaceae.

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Research Article Wed, 22 Mar 2023 15:31:00 +0200
Monophyly and transoceanic dispersal in the widespread floating club-rush clade, Isolepis subgenus Fluitantes (Cyperaceae) https://plecevo.eu/article/84466/ Plant Ecology and Evolution 155(1): 41-50

DOI: 10.5091/plecevo.84466

Authors: Jan-Adriaan Viljoen, Terry Hedderson, Charlotte Sletten Bjorå, Muthama Muasya

Abstract: Background and aims – Numerous lineages in the Western Cape of South Africa show affinities with the floras of tropical Africa and Australasia. Isolepis subgenus Fluitantes, comprising seven to nine species, includes the broadly-defined I. fluitans, which occurs throughout Africa into Europe and Asia, as well as on both sides of the Indian Ocean. Thus, it is well suited for testing the generality of both the Cape-to-Cairo pattern of dispersal and transoceanic dispersal between southern Africa and Australasia.Material and methods – We inferred a dated population-level phylogeny based on new sequence data from the nuclear ITS and the chloroplast atpI–H gene regions. We constructed dispersal–extinction–cladogenesis models in Lagrange to infer ancestral areas and to compare the likelihoods of stepping-stone and long-distance modes of dispersal.Key results – The Fluitantes originated in the Cape about 7 million years ago (mya). They spread stepwise onto the mountains of East Africa and thence into Europe and the islands of the Indian Ocean, seemingly tracking their ancestral habitat. Australasia was colonised by a single long-distance dispersal event ca 3 mya. Incongruence between the plastid and nuclear gene trees was apparent for the Australasian taxa, I. crassiuscula, I. lenticularis, and I. producta, with their atpI–H sequences placing them with I. ludwigii in the Fluitantes and the ITS nrDNA resolving them in the Proliferae. Furthermore, two African taxa (I. graminoides, I. inyangensis) diagnosed on unique morphology are resolved as part of the widespread I. fluitans.Conclusion – This study supports and extends the northward migration model that accounts for the Cape element of the Afromontane flora. Australasia was colonised directly from southern Africa, perhaps assisted by wind or waterfowl. Despite ancient hybridization associated with dispersal, we recognise the three taxa in Australasia as distinct, but synonymise I. graminoides and I. inyangensis into the widespread I. fluitans.

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Research Article Wed, 30 Mar 2022 16:30:00 +0300