Morphological and molecular evidence reject conspecificity of Malagasy and Mascarene Parablechnum (Polypodiopsida, Blechnaceae)

Under the current treatment of the Blechnaceae, only one species of the fern genus Parablechnum is recognised in the western Indian Ocean, often referred to as P. marginatum. Two varieties are currently recognised within it: a type variety present in the Mascarene Islands of Réunion and Mauritius an...

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Detalhes bibliográficos
Autores: Molino De Miguel, Sonia, Lafuente, Irene, Rouhan, Germinal, Medina Bujalance, Rafael
Tipo de documento: artigo
Data de publicação:2022
País:España
Recursos:Universidad Complutense de Madrid (UCM)
Repositório:Docta Complutense
Idioma:inglês
OAI Identifier:oai:docta.ucm.es:20.500.14352/126203
Acesso em linha:https://hdl.handle.net/20.500.14352/126203
Access Level:Acceso aberto
Palavra-chave:582.3
581.9
Biogeography
Madagascar
Parablechnum humbertii
Parablechnum marginatum
Réunion
Sporangiasters
Botánica (Biología)
2417.21 Pteridología
2417.20-1 Taxonomía Vegetal. Plantas Vasculares
2505.01-1 Biogeografía Botánica
Descrição
Resumo:Under the current treatment of the Blechnaceae, only one species of the fern genus Parablechnum is recognised in the western Indian Ocean, often referred to as P. marginatum. Two varieties are currently recognised within it: a type variety present in the Mascarene Islands of Réunion and Mauritius and P. marginatum var. humbertii in Madagascar. Recent molecular evidence suggested that these two varieties are not closely related, questioning their conspecific status. To collect further evidence to support a taxonomic decision, we performed a morphological study based on 57 herbarium specimens comparing traits from general morphology, cross section of the fertile pinnae, sporangia and spores. As a result, Malagasy specimens can be distinguished morphologically from the Mascarene ones by pinna apex and pinna section, the presence of sporangiasters and spore ornamentation. Additionally, spore size analyses resulted in statistically significant differences between both varieties. Our results, aligned with the available phylogenetic data, support that these two taxa should be recognised as separate species and, hence, we propose the necessary new combination and provide full descriptions.