Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Polyporales
Family: Ganodermataceae
Genus: Ganoderma
Species: G. australe
Binomial name: Ganoderma australe
Synonym: Ganoderma applanatum
Common name: Artist's porebracket, Artist's conk, Bracket fungi, Shelf fungi
Ganoderma genus is characterized by basidiocarps that are large, perennial, woody brackets, also called "conks". They are lignicolous, leathery, and either with or without a stem. The fruit bodies typically grow in a fanlike or hoof like form on the trunks of living or dead trees. Their hymenium (fertile layer) is in vertical pores on the underside of the caps. Several species of Ganoderma have been used in traditional Asian medicines for thousands of years. Collectively, the Ganoderma is being investigated for a variety of potential therapeutic benefits.
Ganoderma australe (was G. applanatum) is a bracket fungus with a cosmopolitan distribution in wet rainforests on native or exotic trees. The spore bodies are up to 30-60 cm across, hard, woody-textured, and inedible; they are white at first but soon turn dark red-brown. A new fertile layer is added each year.
This wood-decaying fungus is a pathogen on live sapwood causing white rot which will eventually kill a tree. It can live for several more years on the dead stump using primarily the dead heartwood. It is usually found near the base of trees, often at the site of an old wound.
A peculiarity of this fungus lies in its ability to be as a drawing medium for artists hence its common name Artist's conk. When the minutely pored white under surface is bruised or scratched with a sharp implement, it changes from white to a dark red-brown producing visible lines and shading. Drawings on the white pore layer become permanent when the fungus dries.
A large Ganoderma australe with growth rings
The minutely pored white under surface 
Thanks to Wikipedia for information http://creativecommons.org/licenses/by-sa/3.0/
