Orthotrichum cupulatum Hoffm. ex Brid. var. lithophilum, a new variety of epilithic bristle moss from Tasmania

Orthotrichum cupulatum var. lithophilum is described as a new variety from Tasmania, Australia. The species is primarily characterized by its exserted capsule with cryptoporous stomata, a single peristome with 16 exostome teeth, a bistratose lamina of stem leaves, and a densely hairy vaginula. Molecular data and a brief discussion comparing the newly described variety with the most closely related taxa are also provided. Molecular analyses based on complete plastome sequences clearly separated var. lithophilum from the typical form by 272 molecular diagnostic characters specific for Orthotrichum cupulatum var. lithophilum. The distinctiveness of the new taxon was also confirmed by plastome phylogenomics, which confirmed the monophyly of the new variety and its sister relationship to Orthotrichum cupulatum var. cupulatum.