A revision of Blechnum vulcanicum (Blume) Kuhn and related taxa (Blechnaceae) in malesia and oceania

Abstract

The species included in the Blechnum vulcanicum group are all characterised by the presence of unique, minute, surface outgrowths on various aerial parts of a plant; these have previously in error been described as short hairs. However,these so-called‘hairs’are distinctive and consist of about 4 to 7 cells in a linear arrangement.The species of Blechnum that have this feature are here recognised as a new Section, Blechnum sect. Pilosa T.C.Chambers. The species Blechnum vulcanicum (Blume) Kuhn has been widely cited in taxonomic, floristic and ecological studies for Malesia, Australasia and Oceania, but shows much variation across this wide geographic range. The present study rejects this broad view and recognises a total of 13 species in this group. This includes three new species (Blechnum aequabile T.C.Chambers, B. humile T.C.Chambers and B. megavulcanicum T.C.Chambers), and three new combinations (Blechnum deltoides (Colenso) T.C.Chambers, B. feani (E.D.Br.) T.C.Chambers, and B. tovii (E.D.Br.) T.C.Chambers).