Batrachospermum (Batrachospermales, Rhodophyta) in Australia and New Zealand: New Taxa and Emended Circumscriptions in Sections Aristata, Batrachospermum, Turfosa and Virescentia

Abstract

Fifteen species of Batrachospermum from Australia and New Zealand are documented, including (except for the recently described B. antipodites Entwisle) descriptions, photomicrographs, maps and keys. The temperate region particularly boasts many intriguing and endemic taxa. Ten species are described as being new to science: B. discorum, B. kraftii, B. ranuliferum, B. antiquum, B. theaquum, B. debilis, B. campyloclonum, B. prominens, B. terawhiticum and B. wattsii. Diagnostic characters include trichogyne shape, carpogonium morphology and disposition, carposporophyte morphology (including the presence of indeterminate gonimoblast filaments), carposporangia morphology and some vegetative features such as fascicle cell shape. Batrachospermum cayennense Mont. ex KÜtz., B. arcuatum Kylin, B. anatinum Sirodot are reported for the first time from the Australia–New Zealand region, and the circumscription of the cosmopolitan B. gelatinosum (L.) DC. is expanded. All species have ‘well-developed’ whorls, more or less straight carpogonial branches, and carpogonia with a symmetrical base. Thus they are referable to section Aristata, Batrachospermum, Turfosa or Virescentia. However, many of the new taxa are difficult to allocate in the existing sectional system.