Phylogenetic analysis of the relationships between the taxa in the Eucalyptus angustissima complex have been investigated using RFLP analysis of nuclear genome (Elliott and Byrne 2003) (Voucher specimens at PERTH: W. O’Sullivan 127, 357, 812, 968, 966, 1183, 1190, 1193, 1194). This study assessed populations of E. angustissima subsp. angustissima, E. angustissima subsp. quaerenda, E. foliosa and E. misella and found all four taxa to be genetically distinct. Eucalyptus angustissima was not monophyletic as the two subspecies did not cluster together. Eucalyptus misella was sister species to E. angustissima subsp. angustissima, and E. foliosa was sister species to both these taxa. Eucalyptus angustissima subsp. quaerenda was the most distinct of the four taxa.