https://www.algaebase.org/search/species/detail/?species_id=4991
Lithothamnion phymatodeum Foslie 1902
This name is currently regarded as a synonym of Boreolithothamnion phymatodeum (Foslie) P.W.Gabrielson, Maneveldt, Hughey & V.Pena.

https://www.inaturalist.org/flags/677703