Hydropunctaria amphibia  Taxon de Méditerranée.

    Thallus crustose, markedly tightened to the underlying rock, thin, not glossy, greenish very dark when moist, black to blackish when dry, sometimes slightly cracked, seldomly ribbed radially towards the margin, no visible prothallus or then slashed. Perithecia more or less protruding, conical to hemispherical, with apices eroded, uneven and sometimes nicked (some volcano cone like). Ascospores simple, colourless, narrowly ellipsoid, 12-16 x 6-7 µm, 13-15 x 5-6 µm according to our measurements. Mediterranean taxon, on siliceous rocks of the foreshore, just above sea level. N.B. Very similar by its blackish colour to and often confused with Hydropunctaria maura but this latter is oceanic with flat and little protruding perithecia. N.B. This taxon probably is different from Atlantic and English Channel's  Hydropunctaria amphibia since its habitat is not subjected to tides, in addition its thallus is not ribbed or wrinkled and barely bear typical perithecia (one shall seek for a long time among colonies to find one !). A more complete study would be deserved to clarify its status.*