Volvopluteus gloiocephalus (Stubble rosegill)

Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Pluteaceae
Genus: Volvopluteus
Species: V. gloiocephalus
Binomial name: Volvopluteus gloiocephalus
Synonyms: Volvariella speciosa, Volvariella gloiocephala, Agaricus gloiocephalus, Amanita speciosa , Agaricus speciosus, Volvaria speciosa, Volvaria speciosa var. gloiocephala, Volvariella speciosa var. gloiocephala,
Common names: Stubble rosegill, Big sheath mushroom, Rose-gilled grisette

Volvopluteus gloiocephalus is a saprotrophic, cosmopolitan fungus reported from all continents except Antarctica.
It grows on grassy fields, disturbed ground and accumulations of organic matter like compost or woodchips. It can be solitary, scattered, to gregarious.
Volvopluteus gloiocephalus was for most of the 20th century was known under the names Volvariella gloiocephala or Volvariella speciosa, but recent molecular studies have placed it as the type species of the genus Volvopluteus, newly created in 2011.
Volvopluteus gloiocephalus’s cap is 6-14 cm broad, conic to oval becoming convex and nearly plane at maturity. The cap's colour varies from white to grey or grey-brown. The cap’s surface is viscid when moist. The gills start out as white, becoming salmon coloured on maturity. Spores are pink. The stipe (>18 cm tall, >2 cm thick) is white and has a sack-like volva at the base. A partial veil is absent. Fruiting occurs from late winter to spring.

The mature cap on left has salmon coloured gills.Volvopluteus gloiocephalus (by Ron Pastorino.jpg 

A viscid immature cap
Volvopluteus gloiocephalus 1.jpg

The white gills of a juvenile cap.
Volvopluteus gloiocephalus.jpg 

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