More Florida Lichens, Incl. 10 Cent Tour Pyrenolichens, New York: 151, 1995. Basionym: Arthopyrenia viridescens Coppins - Lichenologist, 20: 322, 1988
Description: Thallus crustose, poorly evident, usually appearing as a whitish to pale brown stain on bark, sometimes with a pinkish hue when fresh. Perithecia black, 0.1-0.2 mm across, circular to ellipsoid, mostly scattered. Involucrellum brown, K+ green; exciple brown in upper part; paler and thinner in lower part, of cellular hyphae, usually without bark cells; pseudoparaphyses 0.8-1 µm thick, persistent, much branched and anastomosing, the cells 4-10 µm long; periphyses absent. Asci 8-spored, obclavate to short-cylindrical, K/I-, fissitunicate, the apical dome with an indistinct ocular chamber, 31-49 x 11-17 µm. Ascospores, 1-septate, hyaline or sometimes turning pale brown when overmature, usually constricted at septum, the upper cell wider than the other, both cells usually biguttulate, without a median constriction, 12-17(-19) x 3.5-4.7 µm. Pycnidia black, 0.04-0.05 mm across, producing either: a) oblong, 2-3-guttulate macroconidia measuring 9-11 x 2-2.5 µm, or, b) ovoid-oblong to bacilliform, eguttulate microconidia measuring c. 4-5 x 1-1.3 µm. Photobiont trentepohlioid. Spot tests: all negative. Chemistry: without lichen substances.
Note: an apparently mainly western species growing on smooth bark, especially of Corylus in undisturbed old-growth forests, also reported from Austria. To be looked for in Italy.
Growth form: Crustose
Reproductive strategy: mainly sexual
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)