Ypsilonidium bananisporum sp. nov. belonging to Ceratobasidiales is described and illustrated. This fungus has all the characteristics of the genus
Ypsilonidium including reticulate-hypochnoid basidiomes, broad hyphae branching at right angles, broadly clavate basidia with two sterigmata,
and basidiospores germinating by repetition. It differs from all hitherto known species in the genus by producing suballantoid
to banana-shaped basidiospores, measuring 19.5–22×5.5–6 μm.
Key Words Ceratobasidiaceae - Japan - taxonomy -
Ypsilonidium bananisporum
Contribution No. 314 of the Tottori Mycological Institute.