Ignatova, E.A., O.I. Kuznetsova, V.E. Fedosov & M.S. Ignatov. On the genus Hedwigia (Hedwigiaceae, Bryophyta) in Russia
Arctoa (2016) 25: 241–277
An integrative molecular and morphological study of the genus Hedwigia in Russia revealed at least five distinct species in its territory. Hedwigia czernyadjevae sp. nov. appears to have a wide distribution in Transbaikalia, Yakutia and high mountains of the Russian Far East, although it never occurs frequently. Previously its specimens were identified as H. stellata, but straight leaf apices, strongly incrassate and porose laminal cells and hairy calyptrae differentiate H. czernyadjevae from this species, in addition to sequence data, which place the Siberian species closer to American H. detonsa. Hedwigia nemoralis sp. nov. occurs in southern regions of Russia, from the Caucasus to the Russian Far East, with one locality in Central European Russia. It was also revealed from eastern North America. It is characterized by a small plant size, shortly acuminate, secund leaves with short, denticulate hyaline hair points and weakly ciliate perichaetial leaves. Hedwigia mollis sp. nov. has shortly recurved leaf margins, weakly sinuose laminal cells and spores 20–25(–28) mm. It was revealed in European Russia, from the southern Murmansk Province and Karelia to the Caucasus, and from South Urals and Altai Mts. Hedwigia ciliata is infrequent in Russia, occurring mainly in the North-Western European Russia, with few localities in its central part. It is characterized by longly recurved leaf margins, sinuose laminal cells and spores (27.5–)30–35(37.5) mm. Numerous collections in herbaria from the Caucasus and Asian Russia are referred to H. emodica, which turned out to be rather uniform by morphology. In addition to long hyaline leaf apices, it is characterized by straight leaves, almost plane leaf margins and dense papillae with thick, obtuse branches. Descriptions and illustrations for all five species of the genus revealed in Russia, as well as a key to the identification of Hedwigia species in Russia are provided. Four of these species received a high support in the molecular phylogenetic analysis based on chloroplast trnL-F, mitochondrial nad5 and nuclear ITS1-2 sequences, while H. emodica was found in an unresolved grade. Some collections require further studies, and this first attempt to estimate the species diversity of Hedwigia in Russia highlights the complicated problems, likely caused by hybridization between closely related species.