Description of Ambrosiozyma oregonensis sp. nov., and reassignment of Candida species of the Ambrosiozyma clade to Ambrosiozyma kashinagacola f.a., comb. nov., Ambrosiozyma llanquihuensis f.a., comb. nov., Ambrosiozyma maleeae f.a., comb. nov., Ambrosiozyma pseudovanderkliftii f.a., comb. nov., and Ambrosiozyma vanderkliftii f.a., comb. nov.

Ambrosiozyma oregonensis sp. nov. is described from two strains, one isolated from a mountain stream in Oregon, USA (NRRL Y-6106(T) = CBS 5560(T)), and a second (NRRL YB-4169) from an unknown substrate from Marion, Illinois, USA. The species forms four hat-shaped ascospores in each deliquescent ascus and appears to be homothallic. Abundant true hyphae are produced with some having apparent dolipore-like septa. Analyses of nuclear gene sequences for the D1/D2 domains of large-subunit rRNA, small-subunit rRNA, translation elongation factor-1α, and subunits B1 and B2 of RNA polymerase II show the proposed novel species to be distinct from other species of the Ambrosiozyma clade. Because of their placement in the Ambrosiozyma clade, Candida kashinagacola, Candida llanquihuensis, Candida maleeae, Candida pseudovanderkliftii and Candida vanderkliftii are reassigned to the genus Ambrosiozyma as new combinations, and the description of the genus Ambrosiozyma is emended to reflect the resulting changes in phenotypic characters.