A marked difference as regards species is noted between the Flora of Minnesota and that of California. Herre[1080] has directed attention to the great similarity between the lichens of the latter state and those of Europe: many European species occur along the coast and nowhere else in America so far as is yet known; as examples he cites, among others, _Calicium hyperellum_, _Lecidea quernea_, _L. aromatica_, _Gyrophora polyrhiza_, _Pertusaria amara_, _Roccella fuciformis_, _R. fucoides_ and _R. tinctoria_. The Scandinavian lichen, _Letharia vulpina_, grows abundantly there and fruits freely; it is very rare in other parts of America. Herre found, however, no specimens of _Cladonia rangiferina_, _Cl. alpestris_ or _Cl. sylvatica_, nor any species of _Graphis_; he is unable to explain these anomalies in distribution, but he considers that the cool equable climate is largely responsible: it is so much more like that of the milder countries of Europe than of the states east of the Sierra Nevada. His contention is supported by a consideration of Japanese lichens. With a somewhat similar climate there is a great preponderance of European forms. Out of 382 species determined by Nylander[1081], 209 were European. There were 17 _Graphideae_, 31 _Parmeliae_, and 23 _Cladoniae_, all of the last named being European. These results of Nylander’s accord well with a short list of 30 species from Japan compiled by Müller[1082] at an earlier date. They were chiefly crustaceous tree-lichens; but the _Cladoniae_ recorded are the familiar British species _Cl. fimbriata_, _Cl. pyxidata_ and _Cl. verticillata_. With the Japanese Flora may be compared a list[1083] of Maingay’s lichens from China, 35 in all. _Collema limosum_, the only representative of Collemaceae in the list, is European, as are the two species of _Ramalina_, _R. gracilenta_ and _R. pollinaria_; four species of _Physcia_ are European, the remaining _Ph. picta_ being a common tropical or subtropical plant. _Lecanora saxicola_, _L. cinerea_, _Placodium callopismum_ and _Pl. citrinum_ are cosmopolitan, other _Lecanorae_ and most of the _Lecideae_ are new. _Graphis scripta_, _Opegrapha subsiderella_ and _Arthonia cinnabarina_—the few Graphideae collected—are more or less familiar home plants. Among the Pyrenocarpei, _Verrucaria_ (_Pyrenula_) _nitida_ occurs; it is a widely distributed tree-lichen. It is unnecessary to describe in detail the British lichens. Some districts have been thoroughly worked, others have barely been touched. The flora as a whole is of a western European type showing the influence of the Gulf Stream, though there is also a representative boreal growth on the moorlands and higher hills, especially in Scotland. Such species as _Parmelia pubescens_, _P. stygia_ and _P. alpicola_ recall the Arctic Circle while _Alectoriae_, _Cetrariae_ and _Gyrophorae_ represent affinity with the colder temperate zone.