Mycorrhizal Cirsium purpuratum improves the growth of Clematis stans in volcanic scoria of Mount Fuji

► AM fungi on Cirsium purpuratum were transmitted to co-planted Clematis stans. ► The growth of C. stans was enhanced by mycorrhizal C. purpuratum. ► C. stans nearest to the mycorrhizal C. purpuratum grew best. ► Greater growth enhancement was induced by bigger C. purpuratum. ► Facilitation mediated by AM fungi was confirmed in a primary succession.