Leaf blister ofQuercus phillyraeoides caused byTaphrina caerulescens

An ascomycete fungus causing an undescribed disease was found on an oak,Quercus phillyraeoides. Naked hymenia appeared on the lower side of leaves, causing slightly swollen spots or blisters that exhibited chlorosis. Ascogneous cells were thick-walled, oval and convex. Asci were cylindric or clavate, without a stalk cell. Ascospores were rarely observed, and numerous blastospores were formed in asci. Mycelium habit was intercellular. Blastospores grew well on PDA and formed pinkish yeast-like colonies. Morphological aspects of the fungus matched well with those ofTaphrina caerulescens. Quercus phillyraeoides is recorded as a new host ofT. caerulescens, and the disease ofQ. phillyraeoides caused by this fungus is termed “leaf blister.”