Oregon brown truffle

The truffle-like fruit bodies of Kalapuya are roughly spherical, with lobes and furrows, and dimensions of typically 12–60 millimetres (1⁄2–2+3⁄8 inches) by 10–45 mm (3⁄8–1+3⁄4 in). The peridium (outer "skin") is up to 2 mm thick, and ranges in color from light yellowish-brown to orange-brown to reddish-brown, usually with darker patches in maturity. The surface texture is rough, as the truffle is covered with flat to rounded warts that are 0.5–3 mm wide; larger warts often have smaller warts on them. Older specimens develop narrow cracks over the surface such that it becomes areolate or rimose. The undersurface of the peridium has an branching basal attachment that is roughly similar in texture to cartilage, and which breaks off readily when the truffle is extracted from the soil. The internal spore-bearing tissue, the gleba, is initially whitish and firm, but develops grayish-brown mottling as it matures. The spores are ellipsoid in shape, with a smooth surface, and contain a large central oil drop surrounded by smaller droplets. The spore dimensions are 32–43 by 25–38 μm, the walls measuring 1–3 μm thick. Although not reactive with Melzer's reagent, spores stain readily with Methyl blue. The asci contain 6 to 8 spores per ascus. They are variably shaped, with dimensions of 70–110 by 60–100 μm, with a stem 10–40 by 6–10 μm, and a forked base. …

The species is known only from the Pacific Northwest region of the United States, where it grows in Douglas fir forests that are up to about 50 years old; the authors suggest that it is obligately symbiotic with this tree. Usually appearing from October through March, fruit bodies grow in the top 2–10 cm (3⁄4–4 in) of soil, beneath soil litter, at elevations ranging from roughly sea level to about 500 m (1,600 ft). It occurs on the west side of Oregon's Cascade Range, as well as in the Coastal Ranges of Oregon and northern California.

The truffle is edible, and has been harvested for culinary purposes, although with less frequency than other Pacific Northwest truffles. Both the flavor and odor of the edible fruit body resemble mature Camembert cheese. One source described the taste as follows: "Served in melted butter on sliced baguette, they reminded of buttered lobster."