Many of my mushroom identifications could be incorrect, so know that I’m doing my best, and I am definitely open to being corrected. And supposedly from what I read this is a difficult mushroom to distinguish from other related species.
Size: Cap is 2-8 cm broad, stem 2-8 cm Family: Tricholomataceae Habitat: Grows on soil and leaf litter in woods and forest, as well as grassy areas. Identification: "The appearance of caps is very variable from specimen to specimen and varies even more through the development life of the fruitbody. The cap is initially convex with a downturned margin, eventually flatenning and sometimes developing a central depression, usually with a small umbo; smooth; slightly greasy; dark grey-brown when moist, turning paler in dry weather; 4 to 8cm across when fully expanded." From first-nature.com