New data on the moss genus Hymenoloma (Bryophyta), with special reference to H. mulahaceni

A molecular and morphological study using two chloroplast molecular markers (rps4 and trnL-F) was carried out with specimens belonging to Hymenoloma mulahaceni, a species described at the end of the 19th century from the Sierra Nevada Mountains in southern Spain as a member of Oreoweisia. The comparison with Asian, European, and North American material of Dicranoweisia intermedia proved the conspecifity of both taxa, which was corroborated by molecular data. Therefore, the distribution area of H. mulahaceni is extended to U.S.A., Canada, Greenland, and several Asian countries (Armenia, Georgia, Tajikistan, and Uzbekistan). We also tested the monophyly of Hymenoloma sensu Ochyra et al. (2003), by including in the analysis the Holarctic taxa assigned to the genus together with Chilean material identified as H. antarcticum (putatively synonymous with the type of Hymenoloma) and H. crispulum. Phylogenetic analysis of basal haplolepidous taxa taking into account different genera, mainly of the Dicranales but also of Bryoxiphiales and Scouleriales, confirmed the monophyly of Hymenoloma and suggested a close relationship with the Scouleriaceae sensu Hedderson et al. (2004), while Dicranoweisia was resolved within Rhabdoweisiaceae. Molecular data helped us to show that Hymenoloma brevipes, morphologically closely related to H. crispulum, is a distinct taxon from H. antarcticum. This challenges the earlier records of H. crispulum from the Southern Hemisphere but a comprehensive revision is necessary to confirm its status in the region. A key to the genera Dicranoweisia and Hymenoloma and the European species of Hymenoloma is included.