Abstract
Sequences of several isolates obtained from fresh leaves of Quercus crispula in Japan showed high similarity with those of Poculum sydowianum in NCBI. Apothecia of P. sydowianum-like fungus were found from Q. cripula leaves as a result of field survey. A detailed morphological examination elucidated the difference between P. sydowianum and this fungus, including the remarkable pigmentation prior to the ascospore germination. Sequences obtained from isolates from Q. crispula leaves, those from ascosporous isolates, and those from isolates of P. sydowianum preserved in CBS was compared. The ITS sequences were almost identical within the Japanese isolates and European isolates, respectively, but differed up to 10% between the groups, supporting that they belong to different species. A new species P. pseudosydowianum is described.