Blue-green Cracking Russula

"Russula parvovirescens" is a basidiomycete mushroom of the genus "Russula". Found in the eastern United States, it was described as new to science in 2006. It is similar in appearance to the more widespread "Russula virescens" and "R. crustosa", but can be distinguished from those species by its smaller stature, and microscopically by the voluminous terminal cells of the cap cuticle.