Scholtens & Hayden in Pohl & Nanz (2023) synonymized eastern Phycitodes reliquellum with western P. mucidella, due to a lack of distinguishing structural and genetic differences, while continuing to treat this species as distinct from P. albatella.

Pohl & Nanz (2023): http://wedgefoundation.org/MONA2.asp

Moth Photographers Group: https://mothphotographersgroup.msstate.edu/species.php?phylo=800649