Macromitrium panduraefolium (Orthotrichaceae, Bryophyta), a new species from New Caledonia, with a key to the aristate Macromitrium species in the Pacific, Malesia and Australasia regions

After the discovery of two Macromitrium species with aristate leaves, new to science, in New Caledonia, another aristate species, M. panduraefolium, is described and commented on herein. It is distinguished from the formerly known species by its smaller size, leaves spirally coiled around the branch axis and branch leaf shape narrower at the middle. Its ecology and its status are discussed. In addition, the author provides a key to the aristate species known from the region including Malesia, Australasia, Pacific Islands and Melanesia.