Graphis bungartzii

Graphis bungartzii is a species of bark-dwelling script lichen in the family Graphidaceae.^[1] Described in 2014 from specimens collected in Jalisco, Mexico, this lichen forms a pale greenish-grey crust on tree bark in seasonally dry tropical forests. The species is characterised by its branched, slit-like fruiting bodies (lirellae) with black, grooved lips, small ascospores divided by cross-walls, and the presence of norstictic and connorstictic acids.

Graphis bungartzii was formally described as a new species in 2014, based on specimens collected at the Chamela Biological Station in the Chamela-Cuixmala Biosphere Reserve, Jalisco, Mexico. The species is distinguished from similar members of Graphis by several features: its branched, slit-like fruiting bodies (lirellae) that break through the surface (erumpent) and have a rim of thallus tissue along the sides (lateral thalline margin); lips (labia) that develop grooves; a fruiting body wall (exciple) that is blackened (carbonized) along the sides; small ascospores divided by cross-walls (transversely septate); and the presence of the chemical compounds norstictic and connorstictic acids. The species name (epithet) honours Frank Bungartz.^[2]

The thallus grows on bark and forms a continuous crust 2–5 cm (0.8–2.0 in) across and up to about 150 μm thick. Its surface is smooth and pale greenish-gray, without a distinct prothallus. In section, it has a cartilaginous upper cortex, an irregular algal layer, and conspicuous clusters of calcium oxalate crystals.^[2]

The apothecia are lirelliform, flexuose, often branched, and erumpent, with the disc concealed. The labia are black and striate, and the exciple is laterally carbonized; the hymenium is clear (not inspersed). Ascospores are colorless, eight per ascus, ellipsoid to fusiform, transversely 5–11-septate, and measure about 25–38 × 5–8 μm. Thin-layer chromatography detects norstictic and connorstictic acids (thallus K+ yellow turning red).^[2]

Graphis bungartzii is known from low elevations in seasonally tropical dry forest in Jalisco, Mexico, in and around the Chamela-Cuixmala Biosphere Reserve. The type locality, about 59 m (194 ft) elevation, is described as a transition between dry forest and taller, more humid semideciduous vegetation along arroyos.^[2]

At the type locality it was found on the bark of Croton and Thouinia (including Thouinia paucidentata). Additional specimens were collected at other dry-forest sites roughly 2–135 km (1.2–83.9 mi) from the type locality, at about 50–300 m (160–980 ft) elevation.^[2]

• List of Graphis (lichen) species