Byssoloma subdiscordans (Nyl.) P. James forme foliicole.
Byssoloma rotuliforme (Müll. .Arg.) R. Sant.
Thallus more or less rounded or oval, 2-10 mm diam., surface uneven, minutely verrucose, pale grey-greenish, pale greenish, prothallus usually absent. Apothecia rounded, 0.2-0.4 mm diam., sometimes clustered and then distorted, disc flat then slightly convex, dark brown-grey when moist blackish when old, exciple cotonny, white, conspicuous, possibly vanishing when old. Ascii 8-spored, 40-45 x 9-10 µm according to the literature, 35-50 x 12-20 µm according to our measures. Ascospores oblong, 3-septate, 10-17 x 3-5 µm according to the literature, 10-15 x 2.5-4 µm according to our measures. Chemical spot tests negative (potentially Pd+ faint orange on fresh thalli). Tropical species, on shaded leaves of evergreen trees and shrubs in humid oceanic woodlands (Buxus, more seldom Abies,...), sometimes but less frequently on barks or rocks. Seems to be a miniature of Byssoloma leucoblepharum of which the thallus is emerald green, apothecia much larger and never blackish, and growing mostly on Quercus barks.