Plectronidium australiense is a species of anamorphic fungus. Known only from Australia, where it grows on the dead branches of Banksia canei, it was described as new to science in 1986. Its conidia have a basal appendage and measure 19–26 by 1.5 μm—shorter and narrower than the similar species P. minor, P. sinense, or P. magnoliae.