Tremella globospora, in the field and in culture

Tremella globospora Reid is described from 32 collections made in British Columbia. The fungus grows directly from within perithecia of species of Valsa and Diaporthe found, in this study, on hosts belonging to seven Angiosperm genera and three of Gymnosperm. Single-spore isolates were made from basidiocarps selected to represent as many variables as possible; both colors (yellow and white) of the basidiocarp, proximity of position on a single twig versus considerable distance between sites, both genera of pyrenomycete host, four genera of seed plants, and collection dates from January to September. Compatibility tests indicated a single species with a modified tetrapolar mating system typical of the genus Tremella. Selected dikaryotic isolates were grown in laboratory culture on simple media, and fertile basidiocarps were produced. Variation in size, color, and consistency of basidiocarps in culture was compared with those in field collections. Clamp connections, branching from the clamp cell, and other microstructures produced in culture are also described. No reaction of T. globospora to Valsa cultures or sterilized Valsa perithecia and extracts was observed.