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 hyper-
trophied, immature smutted shoots of Z. caduciflora is used as a delicate vegetable in
China.
Factors such as temperature, light, hydrogen-ion concentration, nutrient and oxy-
gen 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 also
briefly discussed.
