V. 



THE GEOGRAPHICAL DISTRIBUTION OF 

 MOSSES. 



MOSSES will be found distributed all over the earth's 

 surface, wherever the surroundings are suitable for the 

 germination and development of their spores. 



That this should be so is not astonishing when we con- 

 sider how minute, light, and multitudinous these spores are 

 so minute that in many species a pocket lens is required to 

 render them distinct, so light that every faint breeze carries 

 on it myriads of these germs, so profusely produced that the 

 contents of one capsule, if all germinated, would cover with 

 verdure a large space of land, and any one species might, 

 were circumstances favourable, diffuse itself over the earth's 

 surface. But even with these plants, lowly organized as 

 they are, taking their nutriment mostly from the surrounding 

 atmosphere, and depending but slightly upon the soil for 

 their well-being, even with these there is some sort of 

 selection, so far as habitat is concerned, and a struggle for 

 existence ; and whilst some are cosmopolitan, others appear 

 to be truly limited in their range. 



Thus we find that some species, such as Ceratodon 

 purpureus, Racomitrium lanuginosum, Funaria hygrometrica, 

 Hedwigia dliata, Bryum argenteum, B. capillare^ Hypnum 

 cupressiforme, are recorded in the floras and herbaria from 

 all parts of the globe ; whilst others, as Voitia nivalis, 

 Dawsonia superba, Hookeria Iczte-virens, and others are 

 equally restricted in their range. 



Voitia nivalis, which is a fine moss, appears to be restricted 

 to Europe. 



Hookeria Icete-virens, also a very noticeable species, is 



