20 



ON CAL1FORN1AN MOSSES. 



Whole number of 



Bpeoies in Wesl em 



North America. 





t a 



■85 O 



V, ■ 



« a 



S.1 



£^ 



=j • 



Whole number of 



species in Western 



North America. 





Exclusively 

 AV.X.Amer. 



is 



* a 



£K 

 1* 



No. 21, 1 



Atrichum, . . . 





1 



No. 30, 1 



Physcomitrium, . 





1 



22, 3 



Polytriclmm, . . . 



1 



2 



31, 2 



Ptcrogoniuni, 





2 



23, 1 



Pogonatuin, . 



1 





32, 2 



Loskea, .... 



1 



1 



24, 1 



Aulacomnium, 





1 



38, 2 



Alsla, 



2 





25, 11 



Bryutn, .... 



4 



7 



34, 1 



Ncokcra, .... 



I 





26, 2 



Mnium, .... 



2 





35, 1 



Antitrichia, . 



1 





27, 2 



Bart ram ia, . . • 



1 



1 



36, 1 



Fabronia, .... 





1 



28, 3 



29, 1 



Funaria, .... 

 Enthostodon, . . ■ 



1 



3 



37, 26 



Hypnura, .... 



15 



11 



Total, 121 





45 



.Tfi per cent. 



76 



02 j per ot, 



Our first remark in looking over these tables, is on the scantiness of the Bryological 

 Flora of California, and the small number of genera in which the species arc distributed. 

 Sphagnum, Andrcea,Gamjnjlopus, Didymodon, Meesia,Gnjphcea, Leucodon, Anomodon,Thelia, 

 &c. have, every one of them, a number of representatives in Eastern North America and 

 none in the West. This could be explained perhaps in supposing that we arc still too 

 little acquainted with the mosses of California, and that future researches may bring the 

 discovery of a greater number of species. But from what we know of the climate of that 

 State we must admit, I fear, that this scantiness of mosses is rather real than apparent. 

 The vegetation of the mosses, as everybody knows, is particularly favored by a certain 

 degree of constant humidity, and on the contrary, alternate changes of great humidity and 

 dryness tend to destroy it. Now these last climatic conditions are especially marked in 

 California. Professor William H. Brewer, of the Geological Survey of this State, in a 

 very interesting letter on this subject to Mr. W. S. Sullivant, remarks, that the climate of 

 California is particularly unfavorable to the vegetation of the mosses ; that except a narrow 

 strip near the coast, where the fog which comes in from the Pacific Ocean brings moisture, 

 the supply of mosses is extremely limited. Everywhere cast of the Coast Range;, the cli- 

 mate is so very dry in summer, that no dew is deposited on cold nights. Even on moun- 

 tains of greater altitude, he remarks the same absence of mosses. Professor Brewer as- 

 cended Mount Shasta (altitude 14,400 feet), in September, expecting to find there many 

 Alpine mosses, but found none. Of the Coast Range, which, from its exposure to the fogs 

 of the ocean, is apparently better adapted for the vegetation of the mosses, Mr. Bolander 



