Investigation of yeasts from Antarctic regions revealed that certain species of Candida have heterobasidiomycetous life cycles. Two distinct but overlapping groups of species were found: heterothallic and self-sporulating species. Candida scottii is a heterothallic species with the following life cycle: opposite mating types will conjugate and develop a dikaryotic mycelium with clamp connections. Karyogamy occurs in the teliospore which germinates and produces a promycelium. Meiosis takes place in the promycelium, followed by development of haploid sporidia to complete the life cycle. In addition, C. scottii has a self-sporulating phase. From a single cell, in the apparent absence of mating, a uninucleate mycelium is produced that lacks clamp connections. Teliospores, promycelia and sporidia develop that appear similar to those produced from dikaryotic mycelium. The self-sporulating species have life histories similar to the self-sporulating phase of C. scottii; except that heterothallism has not been observed. Based on these life histories the new genus Leucosporidium is proposed with two heterothallic species (Leu. scottii and Leu. capsuligenum) and five self-sporulating species (Leu. antarcticum, Leu. frigidum, Leu. gelidum, Leu. nivalis and Leu. stokesii. Leu. antarcticum) and Leu. stokesii have not been described under the genus Candida. © 1969 Swets & Zeitlinger.