The authors present detailed descriptions of microscopic features for some of the more common Russula species described by C.H. Peck from the eastern United States. As a result of these analyses, R. uncialis is confirmed as good member of subsect. Lilaceinae of subgenus Incrustatula. R. ventricosipes, R. pectinatoides and R. foetentula are confirmed as members of subgenus Ingratula, with R. ventricosipes being closer related to the R. foetens-group in the strict sense (= Foetentinae sensu M. Bon); with R. pectinatoides being related to the R. amoenolens group (= Pectinatinae M. Bon) and having a different spore ornamentation from what is usually identified under that name in Europe, whereas R. foetentula is reinstated as a good, American species that is related to the R. laurocerasi-group because of its almond smell. The type of R. modesta is clearly different from what is commonly identified as such and is provisionally maintained in a monotypic subsection Modestinae within subgenus Heterophyllidia. Finally, R. flaviceps is transferred from subsection Integroidinae to Chamaeleontinae in subgenus Incrustatula.