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

Stropharia rugosoannulata (Wine cap stropharia)

Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Strophariaceae
Genus: Stropharia
Species: S. rugosoannulata
Binomial name: Stropharia rugosoannulata
Synonyms: Geophila rugosoannulata, Naematoloma rugosoannulatum, Psilocybe rugosoannulata
Common names: Wine cap stropharia, Garden giant, Burgundy mushroom, King stropharia, Godzilla mushroom, Wine-cap, Burgundy-cap, Wine-red Stropharia, Composter Mushroom, Stone Mushroom.

Stropharia rugosoannulata is an agaric of the family Strophariaceae found in Europe and North America. It has been introduced to New Zealand. It is found growing individually, or in large clusters in urban habitats during summer and autumn. They are common often arising from landscaped areas or gardens in wood-chip laden soil or soil that is surrounding wood-chips.
Stropharia rugosoannulata can grow to 20 cm high with a reddish-brown convex to flattening cap up to 5-15 cm across. New developing caps are a wine red to reddish brown colour (there is a pale yellow form), fading to a yellowish brown with age. The caps are convex at first becoming nearly flat and cracked with age. The caps margins sometimes have ragged partial veil remnants. 
The gills which are attached to the stem are white at first, turning greyish-lilac to purple-black with maturity.
The stems are >16 cm long and up to 2 cm thick and usually have a thick, white to yellowish annulus that is striated or grooved on its upper surface and radially split on its underside. They have white rhizomorphs at their base.

Thick white strands (i.e. rhizomorphs) can be seen emanating from the bottom of the stalk,

A group of older mushrooms whose caps have flattened and split.

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