I can't be sure from a photograph, but I strongly suspect that this is a corticioid fungus. Mostly you find such fungi on the protected underside of wood that's lying on the ground, but a few (in more than one genus) are found in the exposed habitat of the bark of trees. They can be spread over a considerable distance, in numerous small patches rather than as one continuous sheet. White is the usual colour for such fungi. Of course there are also white crustose lichens but, in Canberra , when I see something that looks like what you've photographed (especially if it's growing on the trunk or on the underside of a branch), I think it's more likely to be a corticioid fungus.
Describe how you intend to use these images and/or audio files and your request will be sent to the author for consideration.
Your request has been successfully submitted to the author for consideration.
2,167,030 sightings of 20,573 species in 6,801 locations from 11,955 contributors
CCA 3.0 | privacy
We acknowledge the Traditional Owners of this land and acknowledge their continuing connection to their culture. We pay our respects to their Elders past and present.