A description is given of Pichia lachancei sp. nov., a new species of yeast that occurs in association with several Hawaiian plant species of the genera Tetraplasandra, Cheirodendron and Clermontia. The new species is heterothallic and occurs in nature in the haploid as well as the diploid state. Upon conjugation of complementary mating types, zygotes are formed that reproduce by budding as diploid cells. When placed on sporulation medium, four hat-shaped spores are produced which are rapidly released from the ascus. Phylogenetic analysis showed that P. lachancei is most closely related to Pichia rhodanensis and Pichia jadinii. The diploid type strain of P. lachancei, isolated from rotting bark of Tetraplasandra hawaiiensis on the island of Hawaii, is strain UCD-FST 79–9T (= ATCC 201914T = CBS 8557T = NRRL Y-27008T).
A new genus, Mastigobasidium, is proposed for teliospore-forming, xylose-lacking, ballistosporogenous, glucuronate-positive yeasts. The distinguishing features of the genus are: Germination of the teliospore by several long aseptate hyphae; curved phragmometabasidia development on the apices of these hyphae; and production of basidiospores on a peg in clusters. The type strain of heterothallic, nitrate-negative species Mastigobasidium intermedium is VKM Y-2720T (Bullera intermedia type strain) and the allotype strain is VKM Y-2727AL (Sporobolomyces weijmanii type strain).