T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Stereum ostrea (False turkey-tail)

Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Russulales
Family: Stereaceae
Genus: Stereum
Species: S. ostrea
Binomial name: Stereum ostrea
Synonyms: Stereum fasciatum, Stereum lobatum, Stereum versicolor, Thelephora ostrea, Thelephora lobata, Thelephora versicolor β Thelephora fasciata, Stereum australe
Common name: False turkey-tail, Golden curtain crust.

Stereum ostrea is an indigenous, non-endemic basidiomycete fungus. It is a plant pathogen and a wood decay fungus that grows on tree bark. The stemless fruiting body grows >5–7 cm wide. It is shaped like a funnel that has been sliced down one side and is often fan-shaped, semicircular, or irregularly kidney-shaped. It cap has concentric circles of red, orange, yellowish, brown, and buff shades. In old age, greenish shades appear as the result of algae.
Stereum ostrea highly resembles Trametes versicolor the Turkey tail fungi and is thus called the 'False turkey tail'. The stemless fruiting body is shell-like.
The caps underside can be whitish to greyish or pale reddish brown. The difference between true and false turkey tails is found underneath the cap: Stereum ostrea lacks a pore surface (has a smooth underside). It is a crust fungus rather than a polypore. It is tough and inedible.

The photo below shows both the top surface (on the right) and the lower surface (on the left)  A some time the dead log must have been rolled over as normally they grow facing the same direction as in the second photo.

Photo shows why one of its common names is "Golden curtain crust".

The underside

The underside of an old group.

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/