FRUIT BODY: Up to 20cm across.  Starting whitish-cream, this saprobic encrusting fungus eventually turns black and is usually found as several flat patches that may join together to create quite extensive fruiting bodies that cause the bark to peel away.  The surface is covered with many small ostioles from where the spores will be released. With age the fruiting body may start to crack.  To add  'stigma' means 'a spot' and most probably refers to the "spots" or bumps on the crust's surface. GILLS/PORES: N/A. FLESH:Tough and whitish. SPORES: Spores narrow, allantoid, hyaline. HABITAT: Fruits on decaying wood from a variety of deciduous trees including Beech, Hazel, Hawthorn and Silver Birch. SEASON: Common.  Throughout the year. EDIBILITY: Inedible.