Graphidaceae of Central French Guiana

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Graphis schizoloma Müll-Arg. B 25357

Thallus thin, corticolous, epiphloeodal, whitish-gray, cracking, surrounded by indistinct margin, sometimes blackish border visible on bark, tightly appressed to bark and following its contours, surface uneven and matte, ecorticate, often tiny black-specked. Apothecia immersed, lirelline, subasteriform, mostly not confluent centrally, short, wide and evenly exposed, with broadly-rounded apices, up to 1.4 mm long, undulate and irregularly short but ± radiately branching, clustered into subradiate groups, not confluent centrally. Disk 0.08-0.13 mm wide, evenly exposed, brown and densely brown pruinose. Thalline margins slightly raised, narrow and concolorous with thallus, obscure; proper exciple slightly protruding, hymenium trapezoidal, plane to subrounded below and concave above (except when, then plane or convex). Exciple narrow and darkened above and soon pale, lacking below, not carbonized, poorly differentiated. Epihymenium dense and dark-brown, asci short-clavate, 8 spored, spores 6-10 locular 7x18-30µ, mostly hyaline, older moribund spores rich brown, I+ blue. UV-. No lichen substances.

This species is much like Graphina anguina in all respects but lacking lichexanthone (some specimens of G. anguina even lack lichexanthone) and without oblong to ovoid muriform spores. Harris calls this Graphis anguinoides ined. (1995). Also examined: B 18918, B 33148