Graphidaceae of Central French Guiana

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Graphis lumbricina Vainio B 25461

Thallus corticolous, thin, mineral gray-white, continuous, irregularly thickened to form numerous small warts, ± evenly and densely dispersed, black-specked throughout, thinly corticate and not quite shiny, forming smallish thalli up to ca. 5 cm across, surrounded by moderately raised brownish interaction zone, no hypothallus evident, K+ orange, P+ yellow. Medulla with many crystalline inclusions. Apothecia subsessile, quite broad and deeply striate with age, densely clustered to well and irregularly dispersed, not constricted at base, up to 0.8 (usually .2-.8) mm long with prominent thalline margin, apothecia first indicated as warts on thallus, later somewhat naked, black and simple, entire when young to often deeply few-striate and perhaps once-branched with age, carbonized, dimidiate exciple, open below but dark brown hypothecium between carbonized walls, striae exposed to hidden by thalline veil. Hymenium not inspersed, ovoid in cross section. Spores 12x55µ, 14-16 locular, in KOH with much expanded halo, I+. Norstictic acid aggregate.