34 BEITISH MOSSES. 



by the presence on their exteriors of a balsamic or glutinous 

 deposit. To these points of structure they owe their 

 capacity to insinuate themselves into the minutest crevices 

 of rock, to get, for instance, amongst the particles of the 

 oolites, and also to fix themselves in the shifting sands 

 of the sea-coast, and by so fixing themselves to give fixity 

 in return to the sand, and so tend to produce the sand- 

 dunes in many parts of the coast. At some parts of the 

 Northumbrian coast the Racomitrium canescens may be 

 found buried deep in the sand, from which it can scarcely 

 be detached ; and in like manner the sand-dunes of Holland 

 and the west of France have in many places been fixed by 

 Mosses. The forests of firs on the North Sea and the 

 Bay of Biscay thus owe their place of abode to humble 

 Mosses. 



Leaves. When we examine the leaves of Mosses and 

 compare them with the more familiar forms presented to 

 us by the phanerogams, we find ourselves in a new world, 

 and the interest with which we view them is increased 

 when we remember that, according to the view usually 

 accepted, they are, so to speak, a unique phenomenon ; 

 they are not the descendants of any earlier leaves nor the 

 ancestors of any later ones ; they appear thus once, as it 

 were, in the history of the vegetable kingdom, and advance 

 no further. They possess something of the charm which 

 an a7Ta| Aeyo/Aevov exercises over the mind of a philologist. 



We may first note what they are not. They are never 

 opposite, never whorled, never on leaf-stalks, never truly 

 veined, never lobed or compound, never furnished with 

 epidermis or stomata. 



