A new combination for <i>Saxifraga octopetala</i> (Saxifragaceae) and its phylogenetic relationship

Abstract

This study was conducted to address the taxonomic status of the Korean endemic species Saxifraga octopetala, which is sometimes considered conspecific to Micranthes manchuriensis. Extensive molecular phylogenetic analysis using nrITS sequences as well as morphological examination of type specimens of the two species were undertaken to ascertain the phylogenetic position and species delimitation of S. octopetala. In the resulting nrITS trees, a total of 65 accessions representing S. octopetala grouped together and nested within the Micranthes clade, exhibiting a close relationship with M. nelsoniana and M. manchuriensis. Multiple accessions of M. manchuriensis collected from China and Russia also formed a clade, showing a sister group relationship with M. nelsoniana var. pacifica and M. fusca. The ambiguous species entity of S. octopetala is thought to have originated from Nakai's misinterpretation of Wilford's collection (type specimens of M. manchuriensis), which is a complex collection including an inflorescence of M. nelsoniana. In spite of apparent morphological similarity between S. octopetala and M. manchuriensis, they differ in the presence and absence of underground stolons. The distinct position of S. octopetala within the Micranthes clade on the nrITS tree suggests that it should retain species status in Micranthes. Thus a new combination (Micranthes octopetala) is proposed.

Characterization of the complete plastid genome and phylogenetic implication of Micranthes octopetala (Nakai) Y.I.Kim & Y.D.Kim (Saxifragaceae), endemic to Korea

“…Despite controversies regarding the taxonomic position of M. octopetala , this has been majorly resolved in a previous study (Kim et al. 2015 ). M. octopetala was originally included in the genus Saxifraga ( Saxifraga octopetala Nakai 1918), but Kim et al.…”

“…Kim et al. 2015 , which is endemic to Korea, was treated as an independent species in 2015 by Kim et al. ( 2015 ).…”

“… 2015 , which is endemic to Korea, was treated as an independent species in 2015 by Kim et al. ( 2015 ). M. octopetala is a perennial plant that typically attains a height of 15–30 cm and grows on the surface of rocks in the shade of deep mountainous areas.…”

“…M. octopetala was originally included in the genus Saxifraga ( Saxifraga octopetala Nakai 1918), but Kim et al. ( 2015 ) revealed that M. octopetala belongs to the genus Micranthes and proposed a new combination-specific name, Micranthes octopetala . Although M. octopetala was ambiguously treated as M. manchuriensis , according to Kim et al.…”

“…Although M. octopetala was ambiguously treated as M. manchuriensis , according to Kim et al. ( 2015 ), a phylogenetic tree based on the nrITS region demonstrated that M. octopetala and M. manchuriensis formed an independent clade. In particular, M. octopetala was shown to be phylogenetically close to M. nelsoniana and M. manchuriensis , with M. manchuriensis forming a sister group with M. nelsoniana var.…”