is an encapsulated yeast-like fungus that can live in both plants and animals.This species, also known by its teleomorph name, Filobasidiella neoformans, belongs to the broad class of organisms called "club fungi" or Division Basidiomycota, which is one the five major types of fungi. C. neoformans usually grows as a yeast (unicellular) and replicates by budding. Under certain conditions, both in nature and in the laboratory, C. neoformans can grow as a filamentous fungus as pictured here: picture of the organism. When grown as a yeast, C. neoformans has a prominent capsule composed mostly of polysaccharides. Microscopically, the India ink stain is used for easy visualization of the capsule. The particles of ink pigment do not enter the capsule that surrounds the spherical yeast cell, resulting in a zone of clearance or "halo" around the cells.
The species C. neoformans is composed of three variants (v.): C. neoformans v. gattii, v. grubii, and v. neoformans. C. neoformans v. gattii is found mostly in the tropics, but has also been confirmed on southern Vancouver Island on the southwestern coast of Canada. Cryptococcus gattii has recently been shown to be different enough from other subspecies to be elevated to its own species level. C. neoformans v. grubii and v. neoformans have a worldwide distribution and are often found in soil which has been contaminated by bird excrement. The genome sequence of C. neoformans v. neoformans was published in 2005. Recent studies made on Chernobyl Nuclear Power Plant have shown that colonies of Cryptococcus neoformans developed on the ruins of melted down reactor harvest energy of radiation (primary beta radiation from caesium-137) itself.
