Filobasidiella neoformans Kwon-Chung 1976, in Kwon-Chung, Mycologia, 67(6), 1197-1200 (1975).
Diagnosis: Fungus heterothallic, basidia hyaline, produced in groups on hyphae with clamp connections, nonseptate, slender with subglobose to flaskshaped apices, 15-70 µm long, 2.5-3.5 µm wide near base and 4-10 µm wide at the apex, typically producing sessile basidiospores by repetitious budding generally from four spots on the apex; basidiospores in basipetal chains, ovate, elliptical to globose, thin walled, finely rough, 1.8-2.5 µm, germinating on agar to produce blastospores; blastospores also produced by budding from hyphae, ovate, subglobose to globose, 2.5- 10 µm in diam, mostly 3-5 µm diam with mucoid capsule; saprophytic or pathogenic to humans and animals.
Index Fungorum Number: IF314130
Notes: The author have cultured 15 strains of C. neoformans isolated from different clinical specimens on malt extract and sporulation agar in various pairs. A basidiomycetous state was found in four pairs after a total of 3 weeks of incubation, 1 week at 25 oC, and 2 weeks at 15 oC. Sexual reproduction was initiated by conjugation of two yeast cells which was followed by the formation of hyphae with clamp connections. A group of long basidia (Figure 1.) each having a subglobose to flask-shaped apex with sessile basidiospores was produced terminally or laterally from the hyphae. In contrast to Leucosporidium, teliospores were lacking; the basidia were never septate and produced terminal basidiospores. Basidial structures of C. neoformans showed a close relationship with Filabasidium Olive in the monogeneric family Filobasidiaceae Olive of the Ustilaginales. However, there are enough differences in the manner of basidiospore formation to warrant description of a new genus. Formation of basidiospores in species of Filobasidium is not repetitious, whereas the new basidiomycete forms basidiospores in basipetal chains by repetitious budding.
Figure 1. Filobasidiella neoformans. Group of basidia with terminal basidiospores.
Kwon-Chung, K. J. (1975). A new genus, Filobasidiella, the perfect state of Cryptococcus neoformans. Mycologia, 67(6), 1197-1200.