Lichens marins - Lecanora rupicola (L.) Zahlbr. subsp. rupicola s.l.

Lecanora rupicola (L.) Zahlbr. subsp. rupicola s.l.

Lecanora rupicola (L.) Zahlbr. subsp. rupicola s.l.

Description

Crustose thallus generally well defined, cracked surface, more or less rough and warty, whitish, very pale greyish, able to form mosaics in sheltered areas, concolorous hypothallus but often blackish in case of mosaic. Apothecia more or less numerous, immersed in the thallus at first then projecting but not sessile, 0.5 to 3 mm in diameter, disk flat at first then convex to strongly convex and even, but rarely, subglobose, brownish, yellowish-brown, brown-pinkish, thin margin, generally regular in shape and not very sinuous or angular, sometimes partial because not very persistent and disappearing in old age, whitish or lighter. Simple, colourless, elliptical spores, 9-15 x 5-7 µm according to the literature Photobiont: green algae. Thallus: C- most often or more rarely C+ orange, K+ pale yellow, KC+/- yellow, P+/- very pale yellow; disc of apothecia: C- or C+ orange (Very variable, but also because the commercial bleach solution usually used contains sodium hydroxide (NaOH)). Ubiquitous "species" found on not too acidic and sheltered siliceous rocks, old walls, fairly common and able to form small mosaic colonies.

N.B. Quite frequently parasitized by Arthonia varians.

N.B. Highly variable "species" or taxon, related by intermediates difficult to distinguish from Lecanora rupicola subsp. subplanata which has immersed apothecia in the thallus, often with a disc covered with a gray bloom, with only the persistent white margin in relief above the thallus.