An actinomycete strain K14-0274T was isolated from the root of Arisaema thunbergii Blume subsp. urashima (H. Hara) H. Ohashi et J. Murata collected in Japan. The results of phylogenetic analysis based on the 16S rRNA gene sequence indicated thatK14-0274T could be distinguished from the members of all known genera, although it represented a member of the family Streptosporangiaceae . K14-0274T produced sporangium-like spherical vesicles with spores on white aerial mycelia. MK-9 (H4) and MK-9 (H6) were the major menaquinones. The whole-cell hydrolysates contained madurose, glucose, mannose, rhamnose and ribose. The cell-wall amino acids comprise l-alanine, d-alanine, d-glutamic acid and meso-diaminopimelic acid. The N-acyl type of muramic acid was acetyl. Mycolic acids were not detected. Phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositolmannoside were detected. The predominant fatty acids were iso-C16 : 0, 10-methyl-C18 : 0 and C16 : 0. The G+C content of the genomic DNA was 69.7 mol%. On the basis of morphological, phylogenetic and chemotaxonomic characteristics, strain K14-0427T represents a novel genus in the family Streptosporangiaceae , for which the name Rhizohabitans arisaemae gen. nov., sp. nov. is proposed. The type strain is K14-0247T (=NBRC 114594T =TBRC 12948T).