Pollen of Alocasia brisbanensis (F. M. Bailey) Domin at Indooroopilly near Brisbane, and at Tolga Scrub ca. 1,400 km NW of Brisbane, was dimorphic. At the time of pollen extrusion it consisted of (1) normal grains with a diameter range of 32.~9.9 J.Lm and a mean of 40.0 J.Lm, with stainable protoplasm, starch and ability to germinate; and (2) small, aborted grains with a diameter range of 19.0-34.2 fJ.m and a mean of 27.7 fJ.m, and without stainable protoplasm, no starch and inviable. At extrusion the amount of aborted grains ranged from 1.8-14.9% (that is, with high variability) with a mean of 6.5%. The amount of aborted grains in buds and during gaping of the spathe was also highly variable but with means of 7.0% and 5.8% respectively, with an average of 6.4% for the 21,201 total grains examined for all stages.