Ignatova, E.A., O.I. Kuznetsova & M.S. Ignatov. Grimmia beringiensis sp. nova (Grimmiaceae, Bryophyta), a putative case of the intrageneric hybridization

Arctoa (2016) 25: 69–79

doi: 10.15298/arctoa.25.03

Molecular phylogenetic analysis of the nuclear ITS revealed four monophyletic entities within the group of species closely related to Grimmia leibergii–G. jacutuca, often considered within a separate genus Dryptodon. This group includes: (1) G. jacutica, widespread species in northern Asia and penetrating to Alaska in North America; (2) G. beringiensis, sp. nov., known from several localities in Chukotka; (3) G. arcuatifolia, a species of the northern part of the Pacific Northwest, from British Columbia to Alaska; and (4) G. leibergii, that occurs in a more southern range, from California to British Columbia. Three out of these four species fully agree with their position in Grimmia subg. Dryptodon (or genus Dryptodon), by morphology, ITS and also chloroplastic trnL, whereas G. beringiensis has trnL-F sequence almost identical with G. elatior from the subg. Grimmia. This is the second case of incongruence in topology between trees based on nuclear and chloroplastic markers in Grimmia s.l. It differs from the previous one, with G. tergestina, in that the putative hybridization involves a more distantly related taxa, sometimes classified in separate genera, Dryptodon and Grimmia. The broad circumscription of the Grimmia seems to be more appropriate to avoid nomenclatural problems.