Genetic and Morphological Evidence for the Transfer of the Lord Howe Island Endemic Fern Lastreopsis nephrodioides to Parapolystichum (Dryopteridaceae)

The lastreopsid ferns currently comprise four genera, with two of them, Lastreopsis and Parapolystichum , poorly delimited morphologically. Attribution of species to Lastreopsis or Parapolystichum has principally been by phylogenetic analysis of chloroplast DNA sequences. The last of the Australasian species of Lastreopsis to have its phylogenetic placement investigated is Lastreopsis nephrodioides , endemic to Lord Howe Island. Phylogenetic analyses of the chloroplast loci rbc L, trn L‐ trn F, rps 4‐ trn S, and trn G‐ trn R place this species in Parapolystichum and accordingly a new combination is made. A detailed description of Parapolystichum nephrodioides is also given and, with a more detailed understanding of morphological differences between the genera, the morphology of the Lord Howe Island species provides additional support for its placement in Parapolystichum : its spores have auriculate projections rather than being echinulate like Lastreopsis subgenus Rhopalotricha ; and its fronds generally have anadromous venation, which is unknown in Australasian species of Lastreopsis subgenus Lastreopsis but found in several other Parapolystichum species.