Graphidaceae of Central French Guiana

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Graphis tenuescens Nyl. H 33375a

Thallus corticolous, tightly appressed, continuous, quite irregularly bumpy and thickened, covered throughout in small uneven papillae, greenish gray, with an extensive thallus, encircled by narrow to wide black entire border, K+ yellow, P-. Medullar with abundant crystalline inclusions especially near thalline margins of apothecia. Apothecia clustered in weakly asteriform groups, sessile, but appearing emergent due to thick thalline margins, broad at base and papillate (as with thallus), and thinned to light veil apically, so exciple appearing grayish with prominent but narrow pale central canal where labia converge, disk not exposed, up to ca. 5 mm long by .07-0.09 mm wide, ± evenly wide, quite sinuous, regularly but sparsely branched, exciple carbonized throughout, and complete below, entire, hypothecium pale, epihymenium yellowish, not inspersed. Paraphyses capilliform, occasionally anastomosing. Spores 2-4/ascus, thick walled and stout, oblong ended, 10-14 locular, 10-12.5x43 (80)µ long I+ blue. No lichen substances.