Re-assessment of type material of Plagiotheciumnovae-seelandiae Broth. and descriptions of four new Plagiothecium taxa (Bryophyta, Plagiotheciaceae) from Australasia.

A re-examination of the original collection of Plagiotheciumnovae-seelandiae described by Brotherus in 1916 indicated that this material is not homogeneous. Re-examination of the diagnosis of this species and morphological analysis supports that two separate taxa should be distinguished - Plagiotheciumnovae-seelandiaevar.novae-seelandiae and P.novae-seelandiaevar.brotheri var. nov. Also, comparisons with the original collection of Hypnumlamprostachys (= P.lamprostachys ) showed differences, which supported their treatment as separate taxa. Revision of the genus Plagiothecium from Australasia (CANB, CHR, HO, MEL, WELT) and types of other species described from this part of the world ( P.funale and P.lucidum ) supported by the study of their diagnoses, qualitative and quantitative characteristics as well as mathematical analyses (PCA, HCA) allowed the division of the examined material into six separate groups - six separate taxa. Thereby, three distinct taxa are proposed - P.cordatum sp. nov. , P.semimortuum sp. nov. , and P.semimortuumvar.macquariense var. nov. All taxa mentioned above are described in detail, their current known distribution and ecological preferences are also included. In addition, images illustrating their most important taxonomic features, as well as an original key to distinguish individual taxa are presented.