Matsutake: Tricholoma magnivelare
Cap 5-25 cm broad, convex to plano-convex, margin inrolled at first, upturned in age; surface dry to subviscid when moist, white when young, developing yellow to orange or brownish stains in age; flesh thick, white; odor distinctly fragrant.
Gills white, spotted brown in age, crowded, adnate to adnexed to sinuate.
Stipe 4-15 cm long, 1-6 cm broad, solid, equal; flesh tough, white, developing similar colors as the cap; veil sheathing from the base, thick, white, forming a cottony annulus.
Spores 5-7 X 4.5-5.5 µm, subglobose to short elliptical, non-amyloid, smooth. Spore print white.
Scattered to gregarious in soil or duff under tanbark oak, madrone and pine; from late fall to mid-winter.
Edible and highly prized by many for its large size and fragrant aroma. Some eat it raw in salads, while others prefer it cooked.
Called Armillaria ponderosa in older field guides, Tricholoma magnivelare is recognized by its large size, white color which bruises orange-brown, a sheathing cottony veil, and spicy odor. It occurs more commonly in the Pacific Northwest, where it is harvested commercially, than in the S.F. Bay Area.