Abstract: The present study deals with some factors influencing the mode of teliospore germination of Yenia esculenta (P. henn.) Liou (Ustilago esculenta P. Henn.) which is parasitic on water bamboo [Zizania caduciflora (Turcz.) Hand.-Mazz.]. The hypertrophied, immature smutted shoots of Z. caduciflora is used as a delicate vegetable in China. Factors such as temperature, light, hydrogen-ion concentration, nutrient and oxygen play an important role in spore germination. Evidences have been obtained to show that morphological changes of basidiosporophore (conidio-promycelium) have been observed under some unfavorable conditions e. g., higher temperature, higher hydrogen-ion concentration, poor nutrient, complete darkness, etc. The morphology of the basidio-promycelium, however, remains unaffected. On the basis of this unique character, Liou (1949) proposed to erect a new genus (Yenia) for Ustilago esculenta and a new family (Yeniaceae) for the order Ustilaginales. According to present study, it seems to the writer that the validation of Yeniaceae is a reasonable and preferable proposal and merits recognition. The evolution and classification of the order are alsobriefly discussed.