Pholiota mushroom spores. Coloured scanning electron micrograph (SEM) of the gills of a Pholiota sp. mushroom with attached spores (red). Pholiota is a genus of small to medium-sized, fleshy mushrooms in the family Strophariaceae. They are saprobes (feeds on dead organic matter) that typically live on wood. The gills are on the underside of the mushroom's cap and are the structures from which reproductive spores are shed. A mushroom is the umbrella-shaped fruiting body, or sporophore, of certain types of fungi. Magnification: x500 when printed at 10 centimetres wide.