Targeted sequencing supports morphology and embryo features in resolving the classification of Cyperaceae tribe Fuireneae s.l.

International audience

English. Molecular phylogenetic studies based on Sanger sequences have shown that Cyperaceae tribe Fuireneae s.l. is paraphyletic. However, taxonomic sampling in these studies has been poor, topologies have been inconsistent, and support for the backbone of trees has been weak. Moreover, uncertainty still surrounds the morphological limits of Schoenoplectiella, a genus of mainly small, amphicarpic annuals that was recently segregated from Schoenoplectus. Consequently, despite ample evidence from molecular analyses that Fuireneae s.l. might consist of two to four tribal lineages, no taxonomic changes have yet been made. Here, we use the Angiosperms353 enrichment panel for targeted sequencing to (i) clarify the relationships of Fuireneae s.l. with the related tribes Abildgaardieae, Eleocharideae, and Cypereae; (ii) define the limits of Fuireneae s.s., and (iii) test the monophyly of Fuireneae s.l. genera with emphasis on Schoenoplectus and Schoenoplectiella. Using more than a third of Fuireneae s.l. diversity, our phylogenomic analyses strongly support six genera and four major Fuireneae s.l. clades that we recognize as tribes: Bolboschoeneae stat.nov., Fuireneae s.s., Schoenoplecteae, and Pseudoschoeneae tr. nov. These results are consistent with morphological, micromorphological (nutlet epidermal cell shape), and embryo differences detected for each tribe. At the generic level, most sub-Saharan African perennials currently treated in Schoenoplectus are transferred to Schoenoplectiella. Our targeted sequencing results show that these species are nested in Schoenoplectiella, and their treatment here is consistent with micromorphological and embryo characters shared by all Schoenoplectiella species. Keys to recognized tribes and genera are provided.