Stereum hirsutum is a fungus that attacks holm oak dead wood. The basiodiocarps look like thin, wavy shells, until 8 cm diameter. A lot of them appear on fallen branks and stamps of holm oaks. On top, the center of the mushroom is hairy, blueish or greyish, while the external border is smooth and displays circles of different orange shades. Below, the hymenium is smooth, that’s typical from the families that produce crust like mushrooms (fam. corticiacaea and estereacea), different from fungi with porus (fam polyporacea) which are often found on wood as well.
Stereum hirsutum causes a white rot in wood. These mushrooms are found in any wet period, not only autumn.
Together with its parasitic fungus golden ear (Tremella aurantia), Stereum hirsutum is frequent on burnt trunks of holm oak after a forest fire. In the 1st picture, Tremella aurantia shows up amongst the numerous basidiocarps of Stereum hirsutum on a stamp of holm oak that was burst in year 2003, in Els Emprius hilltop, in the natural park of Sant Llorenç del Munt i L’Obac.
[photos Jordi Badia (1st, 2nd, 3rd & 5th), Montserrat Porta and Jordi Badia (4th) and Montserrat Porta (6th & 7th)]