Unknown fungus

Description:

Grey brown caps about 20 mm wide with a deep depression. Cap tops were granular and appeared thinner towards the margins which were slightly frilly. The underside of the mushroom was bright white, smooth with no obvious pores. A smooth, flattened, white stipe flared-upwards without interruption and seemed contiguous with the underside of the cap. The fruiting body seemed to be coming out of a crack in the damp decaying wood.

Habitat:

Spotted on a small decaying piece of wood in a national park.

Notes:

This is the second time I've seen this fungus but can't find an ID. Some features match the description of Laccocephalum tumulosum (Polyporus tuberaster) http://bie.ala.org.au/species/c103b5d2-e... - known to occur in Australia. Assistance with an ID would be greatly appreciated.