Mitochondrial phylogenomics supports splitting the traditionally conceived genus Racomitrium (Bryophyta: Grimmiaceae)
Sawicki, Jakub; Szczecińska, Monika; Bednarek-Ochyra, Halina; Ochyra, Ryszard
The polyphyletic nature of the traditionally interpreted genus Racomitrium Brid. and the necessity of its division into some segregates is confirmed by mitochondrial phylogenomics. Phylogenetic analysis based on the complete mitochondrial genomes revealed some incongruence with plastid/nuclear data in the topology of the main clades and provided strong support for recognition of Niphotrichum Bednarek-Ochyra & Ochyra, Codriophorus P. Beauv. and Bucklandiella Roiv. as separate monophyletic genera. In addition, the new genus Frisvollia Sawicki, Szczecińska, Bednarek-Ochyra & Ochyra is recognised to accommodate F. varia (Mitt.) Sawicki, Szczecińska, Bednarek-Ochyra & Ochyra, a species which has so far been placed in Codriophorus as C. varius (Mitt.) Bednarek-Ochyra & Ochyra. In the phylogenetic analysis Bucklandiella is revealed to be the ancestral genus characterised by some primitive characters including smooth laminal cells and short peristome teeth which are variously divided into two broad segments, undivided or merely perforated. All segregates of the genus Racomitrium are characterised morphologically and a key to their determination is presented.