Morphological and genetic variation within the widespread species Acacia victoriae (Mimosaceae)

Abstract

Morphological variation in Acacia victoriae, a species widespread in arid and semi-arid regions of Australia, was analysed by phenetic methods of classification and ordination. Three morphological groups were identified on the basis of phyllode characters and are treated as subspecies. Populations with short, elliptic and tomentose phyllodes are confirmed as A. victoriae subsp. arida Pedley; this form occurs mainly in central Australia. Populations with linear to oblong, non-tomentose phyllodes are referred to subsp. victoriae; this subspecies is the most variable and widely distributed across Australia. Populations with very long, narrow phyllodes, distributed in northern Australia from the Kimberley to Queensland, are described as fasciaria subsp. nov. A small number of non-tomentose specimens with broad elliptic phyllodes from central Australia require further assessment. Thirteen accessions previously sequenced for internal spacer regions and external spacer regions of ribosomal nuclear DNA showed genetic divergence. Six accessions of subsp. fasciaria formed a clade in a parsimony analysis, confirming that the long phyllode form is genetically distinct.