Graphidaceae of Central French Guiana

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Graphis § Fissurina sp. Harris 33859
Graphis ?homichlodes Redgr.

Thallus thin, epiphloeodal, uniform, continuous, tightly appressed to substrate, yellowish-olive, even and smooth, ca. 40µ thick in small overlapping thalli to ca. 4 cm across, surrounded by entire black narrow border. Thallus shiny and smooth, marked by short-reticulate networks of paler lines where old lirellae were in aggregated patches, current apothecia completely immersed with labia pale and convergent and not at all erect to very slightly raised above, and very slightly darkened orangish-brown about fissure, not branched, slightly wavy, up to 0.6 mm long, completely covered by corticate thallus. Cortex prosoplectenchymatous, flaking off in thin sheets, in 1-2 layers and splitting in cross section, K+ yellowish tinged reddish. Small crystal inclusions along margins of hymenium, not inspersed, more or less elongate-elliptical transversely. Paraphyses simple, eseptate, straight, not clavate. Asci 8-spored; spores 4-locular, 4.5-5x11-12µ, I+ smoky-violet, thick walled, lumina lenticular. No lichen substances.

Also examined B33147, G. ?furfuracea Redgr.: as below except thallus grayish-green, with ± asteriform ascomata, spores 5x20µ. thick prosoplectenchymatous. Redinger separates these two taxa from dumastii apparently based on thallus color.