Inoculation experiments with the teliospores of Puccinia Kusanoi DIET. from the leaves of Plcioblastus (Arundinaria) Simoni NAKAI and P. chino (FRANCH. et SAV.) MAKINO. showed that Deutzia scabra THUNP. var. crenata MAKINO (Saxifragaceae) is one of the alternate hosts. The aecial form produced on Deutzia scabra is identified with Aecidium Deutsiae DIET.