Dermatocarpon miniatum (L.) Mann var. miniatum morpho miniatum

   Thallus foliose, generally made of a unique lobe attached to the substratum by a central holdfast, 1-3 cm diam., more or less circular, incised at margin, margin sometimes recurved, upper surface pruinose, chalk-whitish when dry, pale grey, pale grey-green to pale grey-brown when humid, lower surface smooth to slightly reticulated, pale brown. Numerous perithecia, immersed, 0.2-0.3 mm diam., conspicuous as small black dots dispersed all over the thallus. Ascospores colourless, simple, ellipsoid, 8-14 x 5-7 µm 8-14 x 5-7 µm according to literature, 9-14 x 5-6 µm according to our measurements. Pycnidiospores: 5 x 1 µm according to our measurements. Photobiont: chlorococcoide. Chemical spot tests negative. In Brittany, this species has oceanic trends, growing on more or less humid and vertical walls of calcareous or weakly acidic rocks (kersantite, schists), near the sea shore. N.B. Ressembles to Umbicularia but the latter has no perithecia.

N.B. There is a morph. Dermatocarpon miniatum var. miniatum morpho imbricatum with several interlocking lobes.