This fungus, causing spoilage of canned fruits, was grown on Czapek-Dox solution with 5% glucose, at 24[degree]C, until all the sugar was consumed. Approximately 30% of the glucose was converted to mannitol and 0.5% to a new mould product, byssochlamic acid, C18H20O5. This acid was found to be insoluble in water and to titrate as a tetrabasic acid with addition of 2 molecules of H2O. Above 24[degree] C. growth was more rapid but less byssochlamic acid was produced.