Leucangium carthusianum

About

Leucangium carthusianum is a species of ascomycete fungus. It is commonly known as the Oregon black truffle. It is found in the Pacific Northwest region of North America, where it grows in an ectomycorrhizal association with Douglas-fir. It is commercially collected, usually assisted by a specially trained truffle dog. Mature fruiting bodies can be dug up mostly during winter, but the season can extend from September through April.

Summary from Wikipedia