Coenogonium luteum (Dicks.) Kalb & Lücking.
Dimerella lutea (Dicks.) Trevisan
Thallus sometimes hardly visible, evanescent, grey, grey-greenish, bronze. Apothecia usually numerous, 0.5-2 mm diam., disc flat when dry, convex and slightly translucent when humid, yellow-orange, yellow-apricot, exciple more or less translucent when humid, white-orange when dry, marginpersitent more or less transparent and inconspicuous when moist, distinct and white-orange when dry. Ascii 8-spored, cylindrical, 55-65 x 4-5 (7) µm selon nos mesures according to our measures. Ascospores colourless, narrowly ellipsoid, 1-septate, 8-11 x 2.5-3.5 µm according to literature, 8-11 (12) x 3-4 µm according to our measures. Paraphyses swollen on top. Photobiont: Trentepohlia. Chemical spot tests negative. Common, tropical trends, no specific maritime affinity; on mosses of bark on old deciduous trees of oceanic forests, less frequent on rock mosses, see : Coenogonium luteum forme saxicole. In our prospection area this species is almost always associated to Frullania. See Coenogonium pinetum with smaller apothecia, growing on barks. N.B. Apothecia are numerous only in winter and spring.
This species can be the host of the very rare parasite: Enterographa brezhonega.