Abstract
Six fern species are newly reported or substantiated as indigenous to New Caledonia: Davallia sessilifolia, Dicranopteris caudata, Dryopteris arborescens, Pteris terminalis, Trichomanes atrovirens, and T. kurzii. This is the first record of Dryopteris for New Caledonia. Our findings are based on extensive fieldwork, inspection of specimens in relevant herbaria including type material, comparisons with authoritative references, and phylogenetic analyses of chloroplast DNA sequences. The global and New Caledonian distribution, morphological diagnosis, and conservation status are given for each species. Davallia sessilifolia, Dryopteris arborescens, Pteris terminalis, and Trichomanes atrovirens are provisionally assessed as Critically Endangered or Endangered in New Caledonia, because they have few populations that are each of limited size, and some are also threatened by fire or introduced deer and pigs. While Dicranopteris caudata occurs in open habitats, the others are largely confined to humid habitats at high elevation, or to the wetter forested valleys of north-east Grande Terre. These are the most likely habitats in which to find more populations of these species, but also other new species records and new endemic ferns. Alongside the recent description of several new endemic species, the addition of so many non-endemic indigenous species to a fern and lycophyte flora of approximately 300 species is an indication that considerable work remains to be done in documenting these plants in New Caledonia.