Mycoacia uda (Fr.) Donk. syn. Acia uda (Fr.) Bourd. & Galz. Fruit body resupinate, very thin, bright lemon-yellow becoming more ochraceous with age, covered in crowded slender spines which become purple when treated with a drop of KOH. Cystidioles thin-walled, fusoid. Spores narrowly ellipsoid, 4–6.5 x 2–3.5um. Habitat on fallen branches of deciduous trees. Season all year. Common. Not edible. Found In Europe.