Graphidaceae of Central French Guiana

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Graphis sp. Harris 21887a
(Puerto Rican collection)
B 33155

Thallus thin, matte, whitish to mineral gray, ecorticate to thinly corticate, more or less smooth, uniform, cracked, K+ reddish, P-. Ascomata immersed, disk exposed, short, contorted and ± intertwined in densely clustered areas, not differentiated from the rest of thallus, ca. 4 mm long and 0.03 mm wide exposed, margins white, hardly differentiated to slightly raised, concolorous, exciple ± wanting, much bark included, not at all carbonized, epihymenium dark brown and moderately thick, hymenium ± plane below and rhomboidal in section, not inspersed, spores 6-8 locular 5x18µ, oblong to tapered at one end, I-. No lichen substances.