A REVISION OF THE MOSS GENUS SCIAROMIUM (MITT.) MITT. II. THE SECTION LIMBIDIUM DUSÉN, WITH A DESCRIPTION OF VITTIA GEN. NOV. (VITTIACEAE FAM. NOV.)

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  Fifteen species traditionally placed in the section Limbidium Dusén of Sciaromium (Mitt.) Mitt. are evaluated and they are transferred to the newly described genus Vittia Ochyra, a monotype including only V. pachyloma (Mont.) Ochyra. The remaining species of the section Limbidium, Sciaromium conspissatum (Hook. f. & Wils.) Mitt., S. crassinervatum Mitt., S. obscurifolium Mitt., S. confluens (C. Muell.) Par., S. conspissatulum Par., S. platylomalum Par., S. pachylomatum Par., S. drepanophyllariopsis Par., S. krauseanum Par., S. lonchocormus Par., S. depastum Dusén in Scott, S. nigritum Dusén, S. maritimum Card., S. capense Dix., S. brevicuspis Broth., and S. pachyloma (Mont.) Par. var. brevifolium Thér., are considered synonymous with highly polymorphous, rheophytic V. pachyloma. Additionally several herbarium and invalidly published names, including Sciaromium scoulerioides Dusén in Card., S. tenue Dix., S. negeri Dusén, S. linguifolium Herz., S. plicatum Herz., S. pachyloma (Mont.) Par. var. gracilescens Herz., and S. pachyloma (Mont.) Par. var. gracile Broth. are placed in synonymy with V. pachyloma. All synonymous names are typified and a neotype is selected for V. pachyloma as the original type collection does not seem to exist. The sporophytic features are described for the first time for V. pachyloma. The hypnaceous peristome indicates that Vittia is a hypnobryalean moss and the genus is considered as the only representative of the newly described monogeneric family Vittiaceae that shows close affiliation with the brachythecioid group of families. The Vittiaceae is endemic to the western sector of former Gondwanaland and its geographical range covers the Nothofagus region of South America including the Falkland Islands and the Juan Fernandez Islands, with some disjunct stations known from the northern Andes, eastern Argentina, southeastern Brazil, South Africa, and the two sub-Antarctic islands of South Georgia and Kerguelén. The family is considered as distantly related to the mostly Laurasian Donrichardsiaceae. Presumably both families evolved from a remote, common ancestorial type of Gondwanalandic origin. The phylogenetic position of the Echinodiaceae and Rigodiaceae is briefly assessed and it is suggested that they should be removed to the suborder Hypnodendrineae, in close proximity to the Thamnobryaceae.