Ignatova, E.A., D.Ya. Tubanova, O.D. Tumurova, D.V. Goryunov & O.I. Kuznetsova. When the plant size matters: a new semi-cryptic species of Dicranum from Russia
Arctoa (2015) 24: 471-488
The analysis of nuclear ITS1-2 and chloroplastic trnL-F DNA sequences revealed an undescribed species closely related to D. spadiceum, and it is described as Dicranum schljakovii Ignatova & Tubanova, sp. nova. Its distinctive characters include the smaller size of plants and leaves, and a different leaf shape. Its distribution area covers the southern part of Asian Russia, Yakutia, Russian Far East (Primorsky Territory, Kamchatka, Sakhalin and Kuril Islands) and Urals, plus few localities in Taimyr and a single disjunct locality in Murmansk Province. The distinction of D. spadiceum var. spadiceum and var. subscabrifolium is not confirmed by the molecular markers used in the study. Morphological chracteristics of D. spadiceum are corrected by the addition of some characters of var. subscabrifolium. Synonymization of D. angustum and D. laevidens with D. spadiceum is not confirmed as well, and these two species are not closely related to each other. Descriptions and illustrations for D. spadiceum and D. schljakovii are provided, their distribution and ecology are reviewed, and a key to the identification of species of Dicranum sect. Muehlenbeckia with the addition of D. laevidens is given.