Grifola colensoi

The fruit-body consists of a cap with pores on the underside. There is no stem, the caps are somewhat fan-shaped and appear in large, overlapping groups, all radiating from a common base. The caps may be up to 15 centimetres long, up to about a half centimetre thick and are of a somewhat rubbery texture. The upper surface is grey-brown to dark grey and the underside is whitish. The pores on the underside are easy to see with the naked eye. They may be up to a millimetre wide and may be rounded to slightly elongated radially.

Spore print: white.

The fruit-bodies are found on dead wood and at the bases of live trees. The species has been reported from Australia and New Zealand.

There seems to be a faint possibility that more than one species hides under this name (see the technical note if you’re interested), but for now it seems simplest to ignore that.

Look-alikes

When dark grey, there should be no mistaking it - provided you look for pores on the underside! There are other fungi with clusters of grey caps - but with gills on the underside of the cap. If you have something more brownish, look for the large pores and the caps radiating from a common base.    

Technical note

Cunningham reported clamped generative hyphae; Ryvarden reported the type to have unclamped generative hyphae; Buchanan & Ryvarden said that all collections at the PDD herbarium had clamps – and that the type was now lost. So, perhaps there is ‘clampless colensoi’ but, if so, presumably it is uncommon.    

References:

Buchanan, P.K. & Ryvarden, L. (2000). An annotated checklist of polypore and polypore-like fungi recorded from New Zealand, New Zealand Journal of Botany, 38,265-323.

Cunningham, G.H. (1965), Polyporaceae of New Zealand, DSIR, Wellington.

Ryvarden, L. (1977b), Type studies in the Polyporaceae 10. Species described by M.J. Berkeley, either alone or with other authors, from 1844 to 1855, Norwegian Journal of Botany, 24, 213-230.