Agaricus (Omphalia) Colensoi, Berk.; pusillus, pileo tenui umbilicato glabro, margine involute, stipite graeili furfuraceo glabrescente, lamellis adnato-decurrentibus. HAB . On the ground, amongst sand and on scraps of wood, wet logs, etc., Ngaawapurua, Colenso. White. Pileus an inch or more across, smooth, minutely striate all over when dry, deeply umbilicate; margin involute. Stem 1/2-3/4 of an inch high, not a line thick, attenuated downwards, furfuraceous, at length smooth. Gills moderately broad, adnato-decurrent. The nearest ally of this species is probably A. pyxidatus.

[Notes from Kew Type specimen, PRJ 2010] Kew images.