Phylogenetic analysis of Australian Acacia (Leguminosae : Mimosoideae) by using sequence variations of an intron and two intergenic spacers of chloroplast DNA

Three regions of chloroplast DNA are assessed for their utility for phyloge netic analysis of Acacia subgenus Phyllodineae: psbA-trnH intergenic spacer , the trnL intron and the trnL-trnF intergenic spacer. There are large diff erences in the lengths of the psbA trnH spacer (155-440 bp) and trnL-trnF i ntergenic spacer (101-422 bp) regions, and large multi-residue indels were coded as multistate characters. Overall information content in these region s is relatively low, but the total evidence tree has 12 nodes resolved, fiv e with jackknife support. By using Parkia timoriana as the outgroup, Acacia subgenus Acacia (A. farnesiana) is basal and Acacia subgenus Aculeiferum ( A. senegal) is the sister taxon to subgenus Phyllodineae. Although based on a small sample size, within subgenus Phyllodineae, the results of this stu dy have shown that section Alatae is not monophyletic, section Lycopodiifol iae is monophyletic and Botrycephalae is related to members of section Phyl lodineae with racemose inflorescences.