[2] The genus was originally described by the Swiss scientist Johannes Müller Argoviensis in 1893, who distinguished it from related genera by its unique spore structure and interconnected filaments within its reproductive organs.

Dictyographa lichens are characterised by their elongated, slit-like fruiting bodies and spores that are divided by both vertical and horizontal internal walls.

These lichens are found in various parts of the world, including Africa, the Middle East, and Hawaii, typically growing in coastal environments.

In his description, Müller noted that the genus is characterised by a crustose (crust-like) thallus with chroolepoid gonidia, a type of green algae commonly found in lichen symbioses.

[3] The type species of the genus, Dictyographa arabica, was described by Müller as having a thin, white thallus and lirellae (elongated fruiting bodies) that are linear to spindle-shaped and variably curved.

The perithecium, the layer surrounding the reproductive structures, is black, while the spores are spindle-shaped, multi-septate (divided into several compartments), and measure 30–33 μm in length.

Müller distinguished D. arabica from related species by its prominently emerging but not fully exposed lirellae, which remain narrowly closed even at maturity.

The authors argued that the single character of muriform vs transversely septate ascospores alone does not justify maintaining Dictyographa as a separate genus.

They noted this is similar to other recently revised lichen genera like Arthonia, Graphis, and Strigula which now include species with both muriform and transversely septate ascospores.

[4] However, in 2011, Ertz and Anders Tehler reversed this decision, as molecular phylogenetics results showed that Dictyographa formed a well-sported evolution distinct from Opegrapha.

It has been observed growing on a variety of tree species in these habitats, including Adansonia, Avicennia marina, Commiphora, Rhizophora, and Xylocarpus granatum.

Unlike D. arabica, D. varians has been found in non-coastal environments, with specimens collected from elevations of up to 700 metres above sea level.