A Revision of Adriana (Euphorbiaceae)

Adriana (Euphorbiaceae) is an endemic Australian genus of dioecious shrubs found widely throughout the mainland. Results of a taxonomic revision of Adriana are presented and a new taxonomy is proposed in which three taxa are recognised. Adriana quadripartita (Labill.) Muell. Arg. is a southern Australian, predominantly coastal taxon. Adriana tomentosa Gaudich. is a widely distributed species that exhibits considerable variation in leaf morphology and indumentum, in contrast to basic floral structure which is similar throughout the species, and it comprises two varieties. Adriana tomentosa var. tomentosa is a coastal and inland taxon with a distribution along both eastern and western seaboards and in northern Australia. Adriana tomentosa var. hookeri (F. Muell.) C.L. Gross & M.A. Whalen is an inland taxon occurring in the dry interior from Western Australia to New South Wales. A key to these taxa, descriptions and distribution maps are provided. Morphological variation patterns, the delimitation of taxa and the utility of different morphological characters as diagnostic features in Adriana are discussed.