An undescribed Lactarius species in subgenus Lactifluus, subsect. Volemi has been found in the central region of the Gulf of Mexico area, viz. L. pallidilamellatus. The combination of features with regard to basidiome color, basidiospore size and ornamentation height, and hymenial cystidia (size and wall thickness) distinguish it from its close relative Lactarius lamprocystidiatus from New Guinea. The basidiomes of the new species described here were found growing under Carpinus in a subtropical (mesophytic) forest.