Common Script Lichen

The thallus (the main lichen body) is smooth or only slightly uneven, and is usually whitish green to green-grey, sometimes with a yellowish tinge. The apothecia (spore-producing structures) are typically elongate and script-like, either unbranched or branched, measuring about 5–25 mm long and 1–2 mm wide. Their outer rim (the true exciple) is black and not furrowed, while the disc is narrow and breaks through the surface to become exposed even in dry conditions; it is often dusted with a faint whitish pruina. In most species of Graphis, the disc is concealed when dry, but a small number of species – including G. scripta and close relatives – can have the disc exposed even in dry conditions. Within the genus, a thin whitish pruina on the labia or disc is generally treated as a species-level character. The ascospores are 25–70 × 6–10 μm, spindle- to cylinder-shaped, and divided by 5–15 cross-walls (septa). Pycnidia are rare; when present, they produce very small conidia about 2–5 × about 1 μm. No lichen substances have been detected in this species using thin-layer chromatography.