The cap of Gymnopilus junonius is usually from 5 to 10 centimeters wide, and it has a golden yellow color, sometimes it also has a slightly reddish tone. It is usually covered in small red husks which are usually absent in older specimens. The cap is convex when young, and opened and sometimes concave when old. During and after rain it can be shiny and sticky. The stipe has a color similar to the cap, and is slightly widened, as well as elongated at the bottom. The stipe also has a ring. The gills of this species are dense and light brown colored. Spore print has a rusty brown color.
The flesh reacts with potassium hydroxide forming a red coloration.
It grows on stumps or on the bottom of live trees, usually on oaks, but also on other deciduous trees. It can be found on almost all continents.
Gymnopilus junonius can be found mainly during fall, although on some locations it can be found in the summer as well.
Poisonous. Specimens found in certain parts of North America are hallucinogenic. There is not much information about this property for specimens collected in other parts of the world.
It could eventually be confused with certain other species from the same genus, although in coniferous forests, there are certain species from the Pholiota genus that are similar to Gymnopilus junonius. All of those species are also not edible.