Lecanora campestris subsp. campestris morpho atrata forme sur ardoise.

     We present here a very nitrophilous form of Lecanora campestris subsp. campestris morpho atrata which is characterized by its occurrence on dirty slates in polluted areas rich in ammonia derivatives (pigsties, etc.). The thallus is strongly warty, dirty whitish and the apothecia are often rare and small in size or they only appear in tiny areas of the thallus.