Graphid Lichen (Graphis mucronata)

Small pale greyish-white plaques (photobiont) were seen on moist thick bark of a eucalypt. Each of these plaques had a scribbly lead-grey pattern. These long, branched reproductive parts (Lirellae) are the spore-bearing apothecia.
There were several of these patches on the bark but you had to have a close look to see the 'scribbles'. This was spotted on a tree in the coastal area - Snowy River estuary.