Dirinaria – Foliose lichens.

Ascomycota > Lecanoromycetes > Teloschistales > Caliciaceae.

There are about 3 dozen species of which 12 are found in Australia growing on rocks, bark, wood or moss.

Dirinaria thalli are commonly 2 – 12 cm across but can grow to 20 cm.
Despite being a foliose lichen the thallus is pressed flat onto the substrate and can be firmly attached resembling a crust.

The upper surface can be white to grey, bluish or yellowish-grey, dull yellow and some can have a dark brown centre.
The surface can be shiny or dull and a powdery frosting (pruina) is sometimes present.
With age the centre may become warty or cracked.

The lobes may be radiating from the centre or irregular, discrete or confluent, flat or longitudinally wrinkled or folded, and
    pinnately (or somewhat pinnately) divided.
The lobes can be up to 5 mm wide and the tips may be slightly concave.
The apices may be rounded, squared or fan-shaped.

Isidia &/or soredia may be present.
Soredia can be powder-like or in globular soralia on the lobe surfaces.

The lower surface is black or brown and sometimes there is a paler marginal zone.
There are no cilia or rhizines.