The genus Acromastigum in Australia

Twelve species of Acromastigum (Lepidoziaceae) are recognised for Australia including three new species from Tasmania, Acromastigum prismaticale sp. nov., A. interstisiale sp. nov. and A. fumosum sp. nov. The new species A. interstisiale also occurs in New Zealand on the Denniston Plateau. Acromastigum tenax is a new record for Australia from the Wet Tropics Bioregion, and Acromastigum divaricatum is recorded for Tasmania and New Zealand. The enigmatic New Zealand endemic. Acromastigum brachyphyllum is synonymised with A. anisostomum, which is excluded from the Australian flora as all Australian records are based on misidentifications, primarily of A. interstisiale but also of A. mooreanum and A. fumosum. Acromastigum furcatifolium and A. fumosum are geographically restricted and sparsely distributed, the former on sandstone in rainforest in the Blue Mountains west of Sydney, the latter on peat in rainforest and shrublands in Tasmania. Acromastigum exiguum and A. marginatum are retained as separate species distributed either side of the Tasman Sea. Descriptions, illustrations and associated observations for Australian species of Acromastigum are presented, as is a key including Australian and New Zealand species.