A taxonomic revision of Eucalyptus camaldulensis (Myrtaceae)

Eucalyptus camaldulensis Dehnh. has one of the widest natural distributions of any Australian tree species. It is represented in most climatic zones and the majority of river systems across Australia. Numerous studies have documented morphological and genotypic variation among populations from across its range. Its adaptation to a wide range of environments has contributed to it becoming one of the most widely cultivated eucalypts across a range of arid, temperate and tropical countries. A recent range-wide study of E. camaldulensis with microsatellite markers concluded that its patterns of genetic variation were consistent with it comprising seven infraspecific taxa. As foreshadowed in that study, here we describe these taxa, viz. subsp. acuta, subsp. arida, subsp. camaldulensis, subsp. minima, subsp. obtusa, subsp. refulgens and subsp. simulata. A key to subspecies is presented, with each subspecies being illustrated and the main differences tabulated. Operculum shape, the arrangement of stamens in the bud and the reticulation density of adult leaves are some of the main characters distinguishing taxa. Clustering patterns from further analyses of the microsatellite data were consistent with morphological affinities among subspecies. Typification issues and lignotuber status are among topics discussed.