Phlegmacium lavendulense is a species of fungus in the family Cortinariaceae.

[2] In 1960 it was reclassified as Phlegmacium lavendulense by Meinhard Michael Moser.

[1] In 2022 a genomic study of the family Cortinariaceae transferred many Cortinarius species to new and existing genera.

The basionym Cortinarius lavendulensis was transferred to Phlegmacium and listed in the paper as a novel combination accredited to the mycologists Tuula Niskanen and Kare Liimatainen.

[3] It is native to Australia and was described from a specimen collected in the Mount Lofty Ranges.