Variation in some floral, seed, and growth characteristics of Acacia harpophylla (Brigalow)

Abstract

Statistical and other numerical methods of analysis were used to examine variation in Acacia harpophylla (brigalow), a species of wide occurrence in north-eastern Australia. Experiment indicated that the species is largely cross-pollinated. From material collected in the field floret counts, seed size, longevity, and imbibition and germination rates all revealed substantial variation, possibly of a clinal type, within the species.

In a glasshouse experiment with 255 seedlings measurement of 19 characters revealed wide differences in morphology, growth, and ontogeny. Over the geographic range sampled, much of the variation found would be consistent with selection for adaptation to increasing temperature and aridity.

It is suggested that analogous variation may occur in other Australian species of Acacia.