Fungus which cannot be grown on aificial media is?

Rhinosporidium seeberi REF: Dail and Hammar's Pulmonary Pathology: Non-neoplastic Lung Disease 3rd edition, page 404, The etiologic agent of Rhinosporidiosis, Rhinosporidium seeberi, is an enigmatic microbe that has been difficult to classify. Recently, R. seeberi has been considered a fungus, but it was originally thought to be a protozoan parasite. R. seeberi has not been detected in the environment, and its natural host or reservoir is unknown. Attempts to propagate this organism on aificial media have failed, as has continuous co-cultivation with human cell lines. "The fungus cannot be isolated on synthetic media of transmitted experimentally to animals; however, it will grow in cell culture"