New taxa and new combinations in Australasian Epilobium (Onagraceae)

Abstract

On the basis of extensive field work and the cultivation of several hundred strains in the experimental garden, a revision of the Australasian species of Epilobium (Onagraceae) is being prepared. In the present paper, two new species and two new subspecies are described, all from Australia; three species are reduced to subspecific status; and three other entities, currently regarded as varieties, are raised to the rank of species. The widespread entity usually referred to as Epilobium cinereum A. Rich. is considered to be a subspecies of E. billardierianum Sér., with which it intergrades completely in Australia. On the other hand, Epilobium brunnescens (Cockayne) Raven & Engelhorn of New Zealand is regarded as an entity of specific rank because of its wide sympatric occurrence with and distinctness from E. nerteroides A. Cunn. Introduced populations of this complex which are widespread in the British Isles are regarded as E. brunnescens subsp. brunnescens. It is held that in a group such as Epilobium, in which both autogamy and interspecific hybridisation are frequent and in which the hybrids between well differentiated species are often fertile, a conservative taxonomic treatment is most appropriate and the sympatric occurrence of differentiated entities over a portion of their range is not a significant “test” of their specific status as may be the case in, for example, bisexual animals.