Kingdom:   Fungi
Division:    Basidiomycota
Subdivision: Agaricomycotina
Class:        Agaricomycetes
Order:       Agaricales
Family:      Tricholomataceae
Genus:      Conchomyces
Species:     C. bursiformis
Binominal name:  Conchomyces bursiformis
Synonyms: Hohenbuehelia bursiformis, Resupinatus sordulentus, Agaricus bursiformis, Agaricus euphyllus, Agaricus guilfoylei, Agaricus sordulentus, Pleurotus bursiformis, Pleurotus colensoi, Pleurotus dubius, Pleurotus euphyllus, Pleurotus guilfoylei, Pleurotus sordulentus, Stereum dubium, Agaricus tasmanicus, Pleurotus tasmanicus.

Conchomyces bursiformis is an indigenous, non-endemic fungus found throughout New Zealand on decaying wood especially that from beech trees. It has a smooth pale cream to light brown convex cap (>60 mm wide) which is attached to the wood by a very short stipe.
Gills and spores are white, close and radiating from the point of attachment out to the margins.

Conchomyces bursiformis-005.JPG

This fungus was growing on a dead tree branch in a damp area of the Te Henui valley.
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Conchomyces bursiformis.JPG

The underside of the cap showing the gills which radiate from the point of attachment out to the margins.
Conchomyces bursiformis-004.JPG

This is a photo of an old dying specimen. The gills are usually pure white.
Conchomyces bursiformis-003.JPG 

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