Hymenophyllum pluviatile, a new and uncommon fern from New Zealand

Hymenophyllum pluviatile is described as a new and uncommon fern endemic to New Zealand. Phylogenetic analyses of chloroplast DNA sequences show that H. pluviatile is distinct from the other New Zealand species in Hymenophyllum subgenus Globosa. Hymenophyllum pluviatile can be distinguished from its closest New Zealand relatives, Hymenophyllum australe and Hymenophyllum flexuosum, by a suite of morphological and ecological characters. It is mostly confined to the west coasts of the North and South Islands, in areas of high rainfall. Known populations are scattered and small, and more surveys are required to set an informed conservation ranking. Additionally, our morphological and molecular analyses indicate that New Zealand plants previously sometimes referred to Hymenophyllum atrovirens are indistinguishable from Australian material of H. australe. We consequently accept the following members of subgenus Globosa in New Zealand: H. australe, H. demissum, H. flexuosum and H. pluviatile.