MIXED MATING IN BANKSIA-BROWNII BAXTER EX R BR (PROTEACEAE)

Mating system parameters of the rare and endangered species Banksia br ownii were estimated for two populations using both the mixed mating a nd effective selfing models. Estimates of outcrossing rate were simila r in both populations for both models (mixed mating t Pop. 1=0.68, Pop . 2=0.75; effective selfing t Pop. 1=0.65, Pop. 2=0.73) and were among the lowest reported for undisturbed Banksia populations. Banksia brow nii is killed by fire and the high level of selfing found may be assoc iated with this trait. Multilocus and minimum variance mean i estimate s were similar and the covariance of selfing with gene fixation (D) wa s not significantly different from zero indicating that populations we re not structured and that most of the inbreeding was the result of se lf-fertilisation. The absence of structure was attributed to gene disp ersal through pollen disperse by birds, and selection against inbred s eed. It is suggested that several entire, large populations of this sp ecies together with habitat sufficient to support pollinators be reser ved to conserve this species.