Graphis norstictica is a species of script lichen in the family Graphidaceae. It was described as new to science in 2009. This lichen forms pale greyish patches on tree bark with elongated, branched fruiting structures that contain a chemical compound called norstictic acid. It has been found in tropical regions including the Philippines, Kenya, and Papua New Guinea, where it grows on the bark of trees.
Graphis norstictica was described in 2009 by Alan W. Archer and Robert Lücking from a specimen collected in the Philippines and originally associated with the name Graphis nanodes. The original material of G. nanodes comprised two syntypes, one containing norstictic acid and another lacking lichen substances. Since Edvard Vainio's 1921 description of G. nanodes reported the thallus as Kâ (indicating no reaction in the potassium hydroxide spot test), the chemically negative syntype was designated as the lectotype for that species. The well-developed norstictic acidâÂÂcontaining collection lacked a valid name and was therefore described as G. norstictica; its specific epithet refers to the presence of this lichen product.
The species belongs to a small group of three closely related taxa (G. renschiana, G. borealis, and G. norstictica) that share similar morphology and anatomy (lineola-morph) and similar chemistry but differ in ascospore size.
The thallus of G. norstictica is corticate (having a defined ), smooth to uneven in texture, and white to pale yellowish grey in colour. The âÂÂelongated, often branched fruiting bodies typical of GraphisâÂÂare (breaking through the surface), possess a lateral (rim of thallus tissue on the sides), and are elongate with irregular branching. They measure 1âÂÂ5 mm long by 0.2âÂÂ0.3 mm wide, and their edges () are entire (smooth, without striations). The (rim around the spore-bearing tissue) is laterally (blackened), and the hymenium (spore-bearing layer) is clear, lacking oil droplets or granules. Each ascus contains eight ascospores, which are (divided into many chambers by both transverse and longitudinal septa), colourless (hyaline), and measure 35âÂÂ50 à17âÂÂ25 micrometres.
Graphis norstictica has been recorded from the Philippines, Kenya, and Papua New Guinea. It occurs in habitats suitable for other lineola-morph Graphis species, typically on the bark of trees in tropical or subtropical regions.