 The best known members include the earthball "Scleroderma citrinum", the dye fungus "Pisolithus tinctorius" and the 'prettymouths' of the genus "Calostoma".Fruit-bodies are mostly epigenous (above ground), rarely hypogeous (underground), more or less spherical in shape, without a stem or with an irregular root-like stem.The peridium (outer wall) is mostly simple, rarely 2-layered, firm, rarely thin, membranous, breaking open irregularly or in lobes or decaying, revealing the gleba.