First person to use this name on MO: Erlon Bailey
After a short historical summary of the species in Russula subgenus Compacta subsection Nigricantes in the United States, the microscopic features of the type specimens of four taxa from North America are described and discussed: Russula decora, R. densifolia var. paxilloides, R. sordida and R. subsordida. Previous suggestions of possible synonymies with European taxa are rejected.
Cryptogamie, Mycologie 35(3):293-309. 2014
Illustrations: N. Y. State Mus. Bull, 105. P. 40, Pl. 99, Fig. 1-5.
This species is said by its author to differ from Russula sordida, in its viscid pileus, dingy gills, and changing to blackish more slowly.