140 MOSSES AND LIVERWORTS 



is round and flat. Or again, look at the leaves 

 drawn at fig. 33 of the same plate, taken from 

 Hutchins' Liverwort (Jubula Hutchinsice) ; the 

 tiny under lobe on the lower margin of the leaf 

 is reduced to the very smallest dimensions, and is 

 hardly noticeable, even in the microscope, unless 

 attention is directed to it. The only mosses that 

 have anything in the nature of a double part to 

 the leaf are the members of the Plat Pork-moss 

 (Fissidens) family, but this cannot, from a botanical 

 point of view, be said to be in any way analogous 

 to the bi-lobed leaves of the liverworts. In one 

 respect a large number of the leafy liverworts 

 resemble these Elat Eork-mosses (Fissidens), and 

 some few other families of the moss tribe, namely, 

 in their peculiarly flat growth, all the leaves 

 occupying, so to speak, the same plane; this, as 

 already mentioned, is one of their characteristic 

 features, and often helps to single them out, even 

 at first sight. 



Leaf-cells. The cell-structure of the leaf is a 

 matter of no little importance in distinguishing 

 between the various species, hence a few words 

 on the subject may be added, before concluding. 

 Owing to the fact that in liverwort leaves 

 the cell contents are especially dense, and the 

 leaves in consequence very opaque, it is often 

 most difficult to make out the form of the cells, 

 even with the help of a high magnifying power, 

 and it is generally necessary to treat the leaves 



