Graphidaceae of Central French Guiana

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Graphis sp. Harris 34140a

Thallus corticolous, thin, quite rugose and uneven, matte, yellowish-green, crumbling, surrounded by a narrow entire brown border, K+ orange-red, P+ orange (stictic), UV+ yellow (lichexanthone). Ascomata lirelline, long, few (1-2) branched, immersed, visible as very slightly paler thalline margins, 0.05-0.07 mm wide, about a sunken grayish line where labia converge, lateral margins irregularly thickened and raised above apical thin thalline veil, long, intertwined and quite flexuose 1-3 mm, never straight, blackish exciple easily visible in older material where veil rubbed off, exciple mostly not exposed, few striate above and carbonized below, irregularly but thickly, hymenium hyaline and ± round in cross section, not inspersed, hypohymenium colorless. Paraphyses straight, eseptate, capilliform, spores 8/ascus, 8 locular, 7.5x24µ, oblong to slightly tapered at one end, lumina thick walled and lentiform. Lichexanthone, stictic acid.