The apothecium has a layer of exposed spore-producing cells called "asci" (singular: ascus), and is usually a different color from the thallus tissue. When the apothecium has an outer margin, the margin is called the "exciple". When the exciple has a color similar to colored thallus tissue the apothecium or lichen is called "lecanorine", meaning similar to members of the genus "Lecanora". When the exciple is blackened like carbon it is called "lecideine" meaning similar to members of the genus "Lecidea". When the margin is pale or colorless it is called "biatorine".