Stigmidium marinum (Deakin) Sw.
Common in the coastal zone, commensal of Verrucaria, notably of Verrucaria (Wahlenbergiella) mucosa and less frequently of Verrucaria halizoa. Its development induces a slight modification of the host thallus colour and the presence of perithecia, 150-200 µm diam., little prominent, black when mature. In the case of Verrucaria (Wahlenbergiella) mucosa it is appropriate not to confuse them with pycnidia that are much smaller. Ascospores ellipsoid, 1-septate, septum not constricted, 10-15 x 4-6 µm.*