A novel member of the yeast genus Pichia was recovered 67 times during the period 1971 to 1976. This new species P. heedii was named in honor of William B. Heed. Most strains were isolated from the soft-rot of Lophocereus schottii and from Drosophila pachea, which utilizes L. schottii as a host plant. All strains were found in the Sonoran Desert. The species has 4-spored asci and is heterothallic. P. heedii has metabolic capabilities similar to those of P. membranefaciens, but the base composition of its nuclear DNA is 10-12 mol% lower than that of P. membranefaciens. P. heedii may be differentiated from other cactus-specific Pichia species by its ability to assimilate D-xylose and from P. membranaefaciens by its cactus habitat, small cell size and relatively high maximum temperature of growth.