Phyllachora banksiae is a species of fungus in the family Phyllachoraceae. Originally named Plectosphaera banksiae by Harry Swart, it was placed in the genus Phyllachora in 2001. The type collection was made from a Banksia integrifolia plant in Lake Tyers, Victoria (Australia) in May, 1986. Infection is characterised by leaf spots that have a greyish central area spotted with black ostioles (pores) through which spores are expelled. The mycelium of the fungus grows in the double-layered epidermis of the leaf of the host plant, and penetrates the mesophyll tissue in the center of the colony. Perithecia are up to 400 üm in diameter and are the same thickness as the leaf. The asci (spore-bearing cells) are up to 180 üm long and 15 üm wide. Ascospores are hyaline (translucent), and measure 20âÂÂ25 by 10 üm.