Brachythecium
athrocladum (Mitt.)
Paris, an endemic species of St Helena Island, South Atlantic Ocean, is
re-studied by morphology and molecular markers, nr ITS region and chloroplastic
trnL-F. Molecular markers independently indicate the position of the species in
Brachytheciaceae subfamily Helicodontoideae, especially close to the genera Helicodontium
and Clasmatodon. Common characters of the plants from St Helena with
these genera are discussed. Resulting from these studies, the new genus Sainthelenia
Ignatov & M. Wigginton is described, with a single species, confined in
its distribution to this island.