Allozyme and Morphometric Variation in Two Closely Related Mallee Species from Western Australia, Eucalyptus argutifolia and E. obtusiflora (Myrtaceae)

Abstract

The Eucalyptus series Dumosae is ataxonomic group noted for its complex patterns of variation andintergradations between species. In this study, allozymes and morphometricanalysis of adult characters were used to assess the relationship between twomorphologically similar and geographically contiguous member species endemicto Western Australia, E. argutifolia Grayling & Brooker and E. obtusiflora DC. The results showed noevidence of clinal variation between the two species using either technique,and thus supported the current taxonomy. In addition, morphometric analysisrevealed two discrete groups within E. obtusiflora, andit was suggested that formal recognition of the two different forms waswarranted. Consistent with expectations based on earlier studies, all measuresof genetic variability calculated from allozyme data indicated thatpopulations of the widespread E. obtusiflora maintainmore genetic variation than the geographically restrictedE. argutifolia. Factors contributing to reducedvariation in E. argutifolia are discussed, and it wassuggested that it was primarily due to founder events. Strategies for theconservation of genetic resources of both species are also discussed in lightof the data presented.