Monoecious Nitella species (Characeae, Charophyta) from south-eastern mainland Australia, including Nitella paludigena sp nov.

Identification of Australian species of Nitella is problematic. Several species of monoecious Nitella have been described from south-eastern mainland Australia, but identification of these based on current treatments has been difficult. In response to the discovery of a new monoecious Nitella from the swamps of the Fleurieu Peninsula in South Australia, the monoecious species of Nitella from south-eastern mainland Australia were examined and compared. N. paludigena M. T. Casanova & K. G. Karol is distinguished from other monoecious species on the basis of its overall vegetative morphology and oospore morphology. N. paludigena is found in peaty tea-tree (Leptospermum sp) swamps on the Fleurieu Peninsula in South Australia, and in the south-west of Victoria. A description of the morphology and ecology of the five monoecious Nitella species from south-eastern mainland Australia is given, along with a key.