New species Chara oryzae and a new section Corillionia of Chara (Charales, Charophyceae) from European Mediterranean rice fields

Abstract

European paddy fields harbour a morphologically and genetically unusual charophyte that is distant from any other European species. The new species, Chara oryzae from Mediterranean rice fields, was described using an integrated approach, including scanning electron microscopy and molecular phylogenetics. The combination of monoecy, a triplostichous stem cortex with solitary spine cells, haplostephanous stipulodes, abbreviated branchlet segments with their mostly incomplete diplostichous cortication, and long undifferentiated part of a branchlet distinguish C. oryzae from other Chara species described to date. A unique set of phenotypic characteristics and lack of affinity to Chara sections and subsections prompted us to accommodate the species in a new section Corillionia of the subgenus Chara. C. oryzae could be recognized as a species non-native to Europe because it is known only in rice fields, which have been maintained for centuries in the region studied.

HIGHLIGHTS

• European paddy fields harbour a charophyte with unusual morphology and genotype distant from any European species.• A new species, Chara oryzae, is described using an integrated approach.• A new section, Corillionia, of the subgenus Chara is proposed.

Acknowledgements

Maria Rodrigo and all organizers of the 21st Meeting of the Group of European Charophytologists are kindly acknowledged for exciting excursions in Spanish rice fields, the local authorities of the autonomous community of Valencia and Natural Park Albufera de Valencia for their kind permission to collect specimens, Ilya Eremin and Anna Erst for their assistance in SEM studies, Ricky Taylor for the clarification of environment of C. chrysospora in Southern Africa, Irmgard Blindow for checking the type specimen of C. chrysospora in BM, anonymous reviewers and Juliet Brodie for valuable comments and suggestions.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supplementary Material

The following supplementary material is accessible via the Supplementary Content tab on the article’s online page at https://doi.org/10.1080/09670262.2021.1987527

Supplementary table S1. List of studied specimens of Chara oryzae.

Supplementary table S2. Species name, GenBank accession number and haplotypes for the taxa used in our analyses. Sequences obtained in this study are in bold. Shared haplotypes are highlighted with yellow.

Author contributions

R.E. Romanov: original concept, drafting and editing manuscript, sampling, morphological investigations (LM, SEM); A.Yu. Nikulin: acquiring molecular data; V.Yu. Nikulin: acquiring molecular data, phylogenetic analysis; A.A. Gontcharov: drafting and editing manuscript, phylogenetic analysis.

Additional information

Funding

This work was supported by the Russian Foundation for Basic Research, project No. 20-04-00280, and partly by project No. 121021600184-6 of the Komarov Botanical Institute of the Russian Academy of Sciences and the state order for the Institute for Water and Environmental Problems of the Siberian Branch of the Russian Academy of Sciences, No. 121031200178-8.