Mariorajchenbergia leucoplaca

The fruitbody is a flat polypore. It appears as a white(ish), pored sheet on the underside of wood. The pores are fairly large (from 1-4 per millimetre) and, as Buchanan & Ryvarden note,  fruitbodies also “often form on near-vertical surfaces, resulting in irregular pores”.

The first published description of this species appeared in 1855 (as Polyporus leucoplacus), based on material collected in New Zealand. For many years in more recent times it had been known as Dichomitus leucoplacus and in 2022 was placed in the genus Mariorajchenbergia (named after the Argentine mycologist Mario Rajchenberg).

Apart from New Zealand, this species has bene reported from many areas in eastern Australia (and once from near Alice Springs), a few places in Africa and there is at least one reliable record from Japan.

Look-alikes

Macroscopically it resembles a number of other species and identification relies on microscopic features. The large spores and the form of the hyphae that make up the fruitbodies help to quickly identify this species.  

Reference

P.K. Buchanan & L. Ryvarden, 1993, Type Studies in the Polyporaceae 24*. Species Described by Cleland, Rodway and Cheel, Australian Systematic Botany, 6, 215 – 235.