Parmelia formosana was first described by Zahlbruckner (1933) from Formosa. Asahina (1951, 1952) has since reported it from several localities in Japan, but it has not been reported until now from North America. However, I have collected the species at 18 localities in the southern United States. These records have considerable phytogeographic significance, since P. formosana represents another plant common to eastern Asia and southeastern North America. This paper summarizes our knowledge of this unusual lichen in North America.