Two additional Chiastocaulon species (Marchantiophyta: Plagiochilaceae) from the Wet Tropics Bioregion of north-eastern Queensland

Two additional species of the liverwort genus Chiastocaulon Carl, namely, C. fasciculatum M.A.M.Renner sp. nov. and C. pachycephalum (De Not.) Herzog, are reported from two mountain tops in the north of the Queensland Wet Tropics Bioregion, namely, Mount Finnigan and Thornton Peak. Given the recent completion of a revision for Chiastocaulon in Australia, the new species provides another cogent demonstration that the bryophyte flora of the Wet Tropics Bioregion is incompletely explored and documented. The new species Chiastocaulon fasciculatum is similar to C. dendroides (Nees) Carl, but can be distinguished by leaf shape and dentition, among other characters. The leaves of C. fasciculatum are ovate and bear two or three prominent equally sized teeth, and the ventral leaf margin bears two to eight smaller teeth, whereas the leaves of C. dendroides are elliptic and bear two unequally sized teeth, the postical of which is largest, and the ventral leaf margin is entire. Chiastocaulon fasciculatum, as far as currently known, is endemic to the Wet Tropics Bioregion. Chiastocaulon pachycephalum, of which the type is from Borneo, is reported for Australia for the first time from specimens collected on Mount Finnigan.