About Gyroporus castaneus (Bull.) Quél.
The cap of Gyroporus castaneus ranges from 3 to 10 cm in diameter, and is colored pale to rusty brown, darkening as it ages. The stem shares a similar color to the cap, though it may be lighter at its apex. When the stem is cut vertically, it is common to find multiple cavities of different sizes inside it. Both the cap and stem tend to crack or split during dry periods, or as the mushroom ages. The pores are small and white, turning yellow with age, and are not attached to the stem. They darken slightly when pressed. The tubes are also whitish, and the spore print is pale yellow to straw-colored. The flesh is firm, and does not change color when cut. Gyroporus castaneus is found occasionally in Britain, across continental Europe, and in eastern North America, but it is rare in western North America. It grows either alone or in small groups, forming an ectomycorrhizal relationship with oaks (Quercus). It prefers acidic, sandy soils, and produces fruit from summer to autumn. In New Zealand, it grows in association with Leptospermum. In Asia, it has been recorded in Taiwan. This species is included in the Red Book of Moscow Oblast and the Russian Federation, as well as the Red Lists of several other countries, including Norway and Montenegro.
