Walking along Ash Creek at the Dan Ryan Meadow (Lassen County CA) I noticed a slight mushrump (hump on the surface of the ground caused by a developing fungi) in the sandy soil under a ponderosa pine. Carefully pushing aside the soil I discovered several patches of what I believe are western rhizopogon (Rhizopogon occidentalis).
There are over 100 (I have even read over 200) species in this genus. True identification is difficult and requires chemical and microscopic methods. Often called false-truffles, rhizopogons grow under the ground and only some species are partially emergent.
Western rhizopogon has an irregular, potato-like fruiting body, the skin (peridium) of which is yellow white to greyish and may have networks of fine, brownish mycelial strands on the surface and orangish areas. The interior of the fruiting body is a rubbery spore mass (gleba) composed of tiny chambers. The gleba resembles a sponge when observed closely with a magnifying lens. The western rhizopogon interior is a whitish yellow and with age and maturity becomes olive or brown in color. The smooth spores are a cream color and elongated or spindle shaped.
Western rhizopogon is found in montane two or three needle pine forests throughout the Pacific Northwest and into California and Idaho, especially in sandy soil.
Although the edibility of most rhizopogons is uncertain, western rhizopogon is reputed to be “palatable”. I would not know from experience. Palatable or not to humans, squirrels love western rhizopogons.