Growing on the remains of a Gymnopilus? Fungicolous Mucorales seem generally placed in the genus Spinellus. However, a thesis that I have not seen indicates there can be other genera also involved see Overton, B.E. 1997. Notes on the genus Spinellus with comparisons to other Zygomycetes found in fungicolous associations with Basidiomycetes. M.S. Thesis, Southern Illinois Universty, Carbondale, Illinois. 128 p.