Catillaria subviridis (Nyl.) Zahlbr.

         More or less diffuse crustose thallus, thin and able to reveal the underlaying rock, rimose, beige, grey-green, grey-brown, matt. Apothecia numerous, 0.1-0.3 mm in diameter, disc flat to rarely slightly convex, blackish-brown if wet, black if dry, thin margin a little paler. Subcylindrical asci 45-55 x 10-16 µm with a thick blue I + top. Paraphyses with the apex bearing a blackish-brown "cap". Spores elliptical, 1-septate, 10-16 x 4.5-6 µm. No pycnidia. Photobiont: chlorococcoid with elliptical, ovoid or cylindrical cells. No significant color chemical reactions. Maritime species a little nitrophilous coming on rocks rich in organic matter at the level of Verrucaria maura in the mesic supralittoral zone.

_ Similar appearance and difficult to differentiate in the field from certain species of Catillaria which can venture on the seashore such as: Catillaria chalybeia; Catillaria atomarioides and Catillaria lenticularis which have smaller spores.

N.B. A rather poorly defined species, which is why we present it with reservations and with Cf.