10 ON CALIFORNIAN MOSSES. 



data published formerly,* that of eighty-six species gathered in Japan, thirty-three are 

 proper to that country and described as new ; eight are exclusively common to Japan and 

 Eastern North America, six to Japan and Europe, thirty-one to Japan, Europe, and East- 

 em North America, seven to Japan, Europe, Eastern and Western North America, and 

 two only common to Japan, Europe, and Western North America. From this it is also 

 evident that there is no connection whatever westward between the Bryologia of Europe 

 and that of California ; that this last stands thus entirely isolated, and that to explain its 

 relation with the flora of Southern Europe, we have to look for another cause of distribu- 

 tion than that of a transmission of species through intermediate points. This research is 

 worth making, and to render it more interesting and at the same time more conclusive, 

 the best way, I think, is to present in a tabular arrangement the number of species of 

 each genus inhabiting the eastern and the western side of North America, compared with 

 the number of species of the same genera found in Europe. 



Counting all the species of mosses now known as belonging to Eastern North America, 

 including Drummond's mosses, and those which have been found as far west as the Ilocky 

 Mountains, exclusively of those of Western North America, I find four hundred and 

 ninety-three species. Perhaps a few more not yet recorded, have been found recently by 

 Mr. Thomas P. James, or other American bryologists. Thus the round number five 

 hundred would be reliable enough. Their distribution according to genera is as follows : 



* Characters of some new Musei collected by Charles Wright in the North Pacific Exploring Expedition under 

 the command of Captain John Rodgers by William S. Sullivant and Leo Lesquereux (parnp., 1859). 



