The species Leptogium cellulosum P. M. Jorg. & Tonsberg sp. nov. and L. tac
omae P. M. Jorg. & Tonsberg sp. nov. are described. Leptogium aquale (Arn.)
P. M. Jorg. is recorded as new to America, and it is shown that L. perminu
tum Hedr. and L. nanum Herre are synonyms of L. subtile (Schrad.) Torss. an
d L. biatorinum (Nyl.) Leight., respectively.