Revisiting of Carex sect. Confertiflorae s.l. (Cyperaceae): New data from molecular and morphological evidence and first insights on Carex biogeography in East Asia

Abstract

Carex sect. Confertiflorae s.l. is a medium-sized species group (ca. 40 species) with its center of diversity in E Asia (China and Japan). According to morphological traits, the section has been proposed to split into two sections (sects. Confertiflorae sensu Ohwi and Molliculae Ohwi) up to five different ones (sects. Confertiflorae s.s., Molliculae, Dispalatae Ohwi, Ischnostachyae Ohwi, and Alliiformes Akiyama). Recent phylogenetic reconstructions showed Confertiflorae s.l. not to be monophyletic, as species traditionally considered part of it were found to belong to other clades, whereas species traditionally ascribed to other sections were nested within it. In this study, we investigated the phylogenetic structure, morphological affinities, and biogeographic history of sect. Confertiflorae s.l. We employed a taxon-based approach to explore the morphological affinities of the species considered in sect. Confertiflorae and compared the micromorphology of the nutlets of almost all the taxa using SEM. We included 40 samples representing 31 species/subspecies of sect. Confertiflorae s.l. and used two nuclear (ETS and ITS) and three plastid (trnL-F, matK, and rpl32-trnL UAG ) molecular markers to reconstruct the phylogeny of the group. The phylogenetic analyses confirmed the polyphyly of sect. Confertiflorae s.l., whose representatives were found within five distinct clades. From these, two clades, sect. Confertiflorae and sect. Molliculae, were found to be closely related and contained the majority of the species. The composition of the two clades agreed with the morphological structure of the group, and we confirmed an exclusive combination of features (namely color of basal sheaths, presence of bract sheath, peduncle of lowest spike, inflorescence sex distribution, shape of pistillate glume apex, and color and veins of utricle, among others) characterizing each of the two clades. The origin of the two clades was found to be in the early Pliocene; however, the majority of the diversification events within each clade took place during the Pleistocene. This illustrates that although Asia has been regarded as having little potential ecological space for Carex to diversify due to its climate stability, groups of sedges sub-endemic from that area may have a fairly recent origin related to glaciations. We proposed the rearrangement of sect. Confertiflorae as previously conceived as three independent sections: the monotypic Alliiformes, sect. Molliculae, and sect. Paludosae.

Blumea chishangensis sp. nov. (Asteraceae: Inuleae) from Taiwan and new insights into the phylogeny of Blumea

“…3 ). The conflicts between molecular and morphological data are not rare in plants (e.g., Bremer and Struwe 1992 ; Schuster et al 2018 ; Lu et al 2021 ). These conflicts might infer some convergent evolution and/or hybridization in the evolutionary history (e.g., Ran et al 2018 ; Soreng and Davis 2000 ; Liu et al 2020 ).…”

Collections‐based systematics in the new age of discovery: Celebrating the legacy and life of Professor Wen‐Tsai Wang

“…The categorical analysis of neo‐ and paleoendemism suggested the karst areas in southern China as both “museums” and “cradles” of plant evolution that deserve conservation priority. Lu et al (2021) supported the hypothesis that southern Japan–East China probably served as both the ancestral area and the diversification cradle for Carex sects. Confertiflorae and Molliculae .…”