Two distinctive species of Leptogium (lichenized Ascomycotina, Collemataceae) are described. L. polycarpum P.M.Jørg. & Goward from humid coastal regions has 4-spored asci and bears copious small apothecia all over its upper surface. L. subaridum P.M.Jørg. & Goward from semi-arid intermontane regions of southern British Columbia and northern Washington is easily recognized by its shiny, thick, isidia and special ecology.