48 HISTORY OF BRITISH MOSSES. 



cupving the ground, and the giant trees, instead of being 

 enveloped in warm coats of Hypnum as in colder latitudes, 

 clad with the light and tangled vesture afforded by the 

 OrcMdecB and other gaudy epiphytes or parasites. There is 

 however one exception to this rule in the Octohlepharum, 

 albidv.m, a beautiful white moss — frequently brought home 

 even by unscientific collectors — which invests the stems and 

 branches of cocoa- nut. and other trees beneath the Torrid 

 zone. "Others, of still more uncommon occurrence, are 

 gathered on the burning sands of the deserts in the interior 

 of Southern Africa. ""^ 



As we proceed northwards or southwards from the Line, 

 we find the proportion of mosses and the lower crypto- 

 gamics increase, till we reach such latitudes as are repre- 

 sented by the British Isles, where, as has already been 

 noticed, from our climate and formation of the land being 

 favourable to their growth, a greater variety is found than 

 in any other country of similar extent. Within the Polar 

 Circle, accompanied by lichens, they are almost the only 

 vegetable production ; their variety also is so great, that 

 " Crantz, a celebrated traveller in that barren country, says 

 he had counted above twenty species without rising from 

 the rock on which he was sitting." Martens, another 



