Morphology and Taxonomy of Pachnocybe ferruginea

Pachnocybe ferruginea from Douglas-fir utility poles in western Oregon occurred in two forms. Both forms consisted of dikaryotic mycelium that gave rise to brown capitate basidiocarps. However, one form had associated blastic-sympodial conidia, larger basidiocarps, chlamydospores, and a slower growth rate. Single uninucleate basidiospores of both forms produced dikaryotic mycelium with simple septal pores and holobasidia in which karogamy and meiosis occurred. Thus, P. ferruginea has a primary homothallic life cycle. Spores from conidial isolates gave rise to both basidiocarps and the conidial form demonstrating that the conidial form is the anamorph of P. ferruginea. Nevertheless, results suggest that the P. ferruginea variants form a single pleomorphic species corresponding to published descriptions of P. ferruginea, but with an anamorphic stage. The species should be placed in the Chionosphaeraceae.