Bryophyte flora of the Huon Peninsula, Papua New Guinea. LXVII. Amphidium (Rhabdoweisiaceae, Musci)

Amphidium tortuosum (Hornsch.) Cufod. is the only species of the family Rha bdoweisiaceae occurring in Western Melanesia and New Guinea. Both collectio ns came from cliff walls, one of them was in an open grassland area and the other in closed montane rainforest. The placement of Amphidium Schimp. in the neighbourhood of Dicranaceae and in the family Rhabdoweisiaceae instead of Orthotrichaceae is based on the presence of epigametophytic plants in A mphidium, which are unknown in the Orthotrichaceae, on the rhizoid topograp hy similar to Dicranaceae and different from that in Orthotrichaceae, the p attern of papillosity of leaf cells, and on recent evidence from nucleotide sequences.