The genus is notable for its unique reproductive structures and its apparent rarity, having been found in only a few locations despite growing in a relatively common type of forest.

The family is now defined as lichenised ascomycetes with a crustose thallus containing a coccoid green photobiont, hemiangiocarpous apothecia, eight-spored Elixia-type asci, simple hyaline ascospores, and either aliphatic acids or no lichen substances.

[1] Meridianelia is a lichen genus characterised by a crust-like, thin outer layer (thallus) that forms spreading colonies up to 10–20 cm wide.

Like all lichens, Meridianelia is a symbiotic organism, containing a green algal partner (photobiont) with round to oval cells, 9–20 by 9–16 μm, typically clustered in bundles within the thallus.

The surface of the disc starts deeply concave, becoming flat to wavy, dark grey, and covered with a thick whitish powder-like coating (pruina).

The apothecium is surrounded by a very thin layer of fungal tissue (excipulum), measuring up to about 10 μm thick, pale greyish green, composed of interwoven thread-like structures (hyphae).

They are thin-walled, without a gel coating, and round to oval in shape, typically measuring 14–23 by 9–20 μm, often containing a single, large bubble-like structure (vacuole).

It has been recorded in open subalpine woodland dominated by Eucalyptus coccifera, typically growing on dolerite boulder fields at elevations around 950–1010 metres above sea level.

The species forms conspicuous white patches up to 20 cm wide on the lowermost 1–2 metres of eucalypt trunks, as well as on larger individuals of Olearia with loose, papery bark.