The morphological characteristics of Ganoderma basidiomata from infected oil palms from three inland estates showed some variations, but all fall within the description of G. boninense, based on Steyaert s classification system (1967, 1975). Pairings of G. boninense isolates from the same estate showed that there was somatic incompatibility among the isolates which indicated that the isolates were distinct individuals and not clones of single genotypes