Plant Diversity ›› 2021, Vol. 43 ›› Issue (04): 299-307.DOI: 10.1016/j.pld.2020.11.001

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Phylogenetic estimation and morphological evolution of Alsineae (Caryophyllaceae) shed new insight into the taxonomic status of the genus Pseudocerastium

Gang Yaoa, Bine Xueb, Kun Liuc, Yuling Lia, Jiuxiang Huanga, Junwen Zhaid   

  1. a College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, 510642, China;
    b College of Horticulture and Landscape Architecture, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, Guangdong, China;
    c College of Life Sciences, Anhui Normal University, Wuhu, 241000, Anhui, China;
    d College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China
  • Received:2020-06-01 Revised:2020-10-29 Online:2021-08-25 Published:2021-09-07
  • Contact: Junwen Zhai
  • Supported by:
    The authors are indebted to Dr. Xinxin Zhu from Xinyang Normal University, China, for providing field images of Cerastium jiuhuashanense and C. wilsonii, for Dr. Jacob B. Landis from Cornell University, USA, for revising the English writing. This study was financially supported by grant awards from the Natural Science Foundation of Guangdong Province, China (2019A1515011695) and the National Natural Science Foundation of China (31500180).

Abstract: Pseudocerastium is a monotypic genus in Caryophyllaceae endemic to China. The genus has been widely accepted since it was described in 1998, however its phylogenetic position within Caryophyllaceae has never been studied. In the present study, the whole plastid genome and nuclear ribosomal internal transcribed spacer (ITS) sequences of Pseudocerastium stellarioides was obtained through genome skimming, and the phylogenetic position of the species was studied for the first time. Plastid phylogenomic analysis of Caryophyllaceae revealed that Pseudocerastium is clustered within the tribe Alsineae with strong support. Phylogenetic analyses based on an enlarged taxon sampling of Alsineae using five DNA regions (matK, rbcL, rps16 intron, trnL-F and ITS) revealed that P. stellarioides was nested deeply within Cerastium with strong support. Analyses of morphological character evolution suggest that the ancestral states in Alsineae include three styles and a six-lobed capsule at the apex, while both Cerastium and Pseudocerastium have five styles and ten lobes at the apex of the capsule, further supporting their close relationship. The species Pseudocerastium stellarioides is similar to Cerastium wilsonii in morphology, but differs in having villous indumentum on the lower part of the filaments and compressed globose seeds. Therefore, based on the present molecular and morphological evidence, the generic name Pseudocerastium is reduced here as a new synonym of Cerastium and the species P. stellarioides is transferred to Cerastium as C. jiuhuashanense.

Key words: Alsineae, Cerastium, Character evolution, Genome skimming, Molecular phylogeny, Taxonomy