ALLOZYME AND MORPHOMETRIC VARIATION IN 2 CLOSELY-RELATED MALLEE SPECIES FROM WESTERN-AUSTRALIA, EUCALYPTUS-ARGUTIFOLIA AND EUCALYPTUS-OBTUSIFLORA (MYRTACEAE)

The Eucalyptus series Dumosae is a taxonomic group noted for its compl ex patterns of variation and intergradations between species. In this study, allozymes and morphometric analysis of adult characters were us ed to assess the relationship between two morphologically similar and geographically contiguous member species endemic to Western Australia, E. argutifolia Grayling & Brooker and E. obtusiflora DC. The results showed no evidence of clinal variation between the two species using e ither technique, and thus supported the current taxonomy. In addition, morphometric analysis revealed two discrete groups within E. obtusifl ora, and it was suggested that formal recognition of the two different forms was warranted. Consistent with expectations based on earlier st udies, all measures of genetic variability calculated from allozyme da ta indicated that populations of the widespread E. obtusiflora maintai n more genetic variation than the geographically restricted E. argutif olia. Factors contributing to reduced variation in E. argutifolia are discussed, and it was suggested that it was primarily due to founder e vents. Strategies for the conservation of genetic resources of both sp ecies are also discussed in light of the data presented.