A novel endophytic actinobacterium, designated strain EUM 378 ^T, was isolated from the surface-sterilized root tissue of Eucalyptus microcarpa, a eucalyptus tree known as Grey Box. Phylogenetic evaluation based on 16S rRNA gene sequence analysis, including alignment with taxon-specific 16S rRNA gene signature nucleotides, placed this isolate as a member of the family Nocardioidaceae. Strain EUM 378 ^T showed.5.5% 16S rRNA gene sequence divergence from other members of this family and was related most closely to Actinopolymorpha alba YIM 48868 ^T (94.2%) and Actinopolymorpha singaporensis IM 7744 ^T (94.4%). This Gram-positive, aerobic actinobacterium has well-developed substrate mycelia that fragment into small rods. Chemotaxonomic data revealed that the cell wall contains LL-diaminopimelic acid, ribose, glucose and rhamnose. MK-10(H ₆) is the predominant menaquinone. Chemotaxonomic and phylogenetic evidence confirmed that strain EUM 378T represents a novel species of a new genus, for which the name Flindersiella endophytica gen. nov., sp. nov. is proposed. The type strain is EUM 378 ^T