Two species, Icosidesmus tumidus and Icosidesmus latidens are restricted to the lowlands of South Canterbury. The former tends to be in the wetter forest/shrubland habitats whilst the latter is in those which can be very dry and, at the extreme, almost devoid of shrubs. Icosidesmus worthingtoni is very widespread in Central Otago shrublands, dry Nothofagus forests and screes. Icosidesmus longisetosus is restricted to a small area of very wet forests in Fiordland.