About Graphis scripta (L.) Ach.
Graphis scripta (L.) Ach. is a lichen species whose main body (the thallus) is smooth or only slightly uneven. It is typically whitish green to green-grey, and sometimes has a yellowish tinge. Its spore-producing structures, called apothecia, are characteristically elongated and shaped like writing (script-like). They can be either unbranched or branched, and measure roughly 5–25 mm long and 1–2 mm wide. The outer rim of the apothecia, known as the true exciple, is black and has no furrows. The apothecial disc is narrow, and it breaks through the thallus surface to stay exposed even when conditions are dry. This disc is often covered with a faint whitish powdery coating called pruina. Unlike most Graphis species, which keep their apothecial disc concealed when dry, G. scripta and its close relatives are among the small number of species in the genus that have an exposed disc even in dry conditions. Within the Graphis genus, the presence of a thin whitish pruina on the apothecial labia or disc is generally recognized as a characteristic that helps distinguish this species from others. The ascospores of G. scripta measure 25–70 × 6–10 μm, are spindle-shaped to cylinder-shaped, and have 5–15 cross-dividing walls called septa. Reproductive structures called pycnidia are rare in this species; when they do occur, they produce very small conidia that are roughly 2–5 × about 1 μm. No lichen substances have been detected in G. scripta through thin-layer chromatography testing.
