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11 August 2021 Systematics of the Giant Sedges of Carex Sect. Rhynchocystis (Cyperaceae) in Macaronesia with Description of Two New Species
Mónica Míguez, Pedro Jiménez-Mejías, Carmen Benítez-Benítez, Hanno Schaefer, Santiago Martín-Bravo
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Abstract

Populations of Carex sect. Rhynchocystis (Cyperaceae) from the Macaronesian archipelagos (Azores and Madeira) have traditionally been treated either as a variety of the widely distributed Western Palearctic C. pendula, or directly synonymized under it. However, recent phylogenetic studies have shown that Azorean populations of C. pendula display a certain degree of differentiation from mainland plants, while the phylogenetic relationships of Madeiran populations remain unclear. Here we perform an integrated systematic study focused on the Macaronesian populations of Carex sect. Rhynchocystis to elucidate their phylogenetic relationships and taxonomic status. We reconstructed a molecular phylogeny based on five DNA regions and conducted a multivariate morphological analysis. Divergence time estimates show that the Macaronesian populations can be traced back to a Plio-Pleistocene origin. Our results suggest that these island populations of C. pendula are better treated as two distinct species within Carex sect. Rhynchocystis (i.e. C. leviosa from the Azores and C. sequeirae from Madeira). We provide morphological characters to differentiate the new species from C. pendula s. s., detailed descriptions of the three taxa, a revised key for the entire section, as well as detailed analytical drawings of the two newly described species. We also perform a critical evaluation of the taxonomic diversity of Carex in the Azores and Madeira. Finally, we informally assessed the conservation status of the new species at a global scale under IUCN categories and criteria, resulting in the proposal of the categories Least Concern for C. leviosa and Critically Endangered for C. sequeirae.

© Copyright 2021 by the American Society of Plant Taxonomists
Mónica Míguez, Pedro Jiménez-Mejías, Carmen Benítez-Benítez, Hanno Schaefer, and Santiago Martín-Bravo "Systematics of the Giant Sedges of Carex Sect. Rhynchocystis (Cyperaceae) in Macaronesia with Description of Two New Species," Systematic Botany 46(2), 304-320, (11 August 2021). https://doi.org/10.1600/036364421X16231782047442
Published: 11 August 2021
JOURNAL ARTICLE
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KEYWORDS
Azores
budding speciation
island endemism
Madeira
taxonomy
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