Hiya distans (Dennstaedtiaceae), a new combination for an Australasian fern previously classified in Hypolepis.

Three tropical fern species previously treated in the Dennstaedtiaceae genus Hypolepis were recently segregated in a new genus, Hiya, based on phylogenetic analysis of chloroplast DNA sequences and assessment of their morphology. That study specifically mentioned the uncertain placement of the Australasian species Hypolepis distans, which has long been regarded as anomalous within Hypolepis. Using phylogenetic analysis of rbcL and rpl16 sequences, along with morphological and cytological characters, we show that Hypolepis distans is best placed in Hiya, and make the new combination Hiya distans. However, this requires a significant adjustment in the morphological characterisation of Hiya. It can be recognised by the adaxial sulcus of the primary pinnae being confluent with the rachis, veins which reach the lamina margin at an indentation, and the primary pinnae arising at ± 90° from the rachis. It is also a significant ecological extension of Hiya, from the tropical highlands of Malesia and Central and South American to the lowlands of temperate Australasia. [ABSTRACT FROM AUTHOR]