106 MOSSES AND LIVERWORTS 



to the thin walls of the cells themselves. Then, 

 again, the plants very frequently have a markedly 

 flat growth, the leaves heing pretty much on the 

 same plane, so to speak ; this is a characteristic 

 which is not very often met with in the mosses, 

 though occasionally, as in the Elat Eork-moss 

 (Fissidens) family, to which reference has several 

 times heen made, we find a striking instance of it. 

 The shape of the leaves, too, in most liverworts 

 is quite distinct, as a comparison of the drawings 

 in Plate VII. with those in Plate X. will abun- 

 dantly testify. At the same time there are a few 

 mosses the leaves of which bear some resemblance 

 to those of a liverwort, both as regards form and 

 cell-structure. Eor instance, the Dotted Thyme 

 Thread-moss (Mnium punctatum> Plate II. fig. 2) 

 has specially large leaf-cells, to which fact it 

 owes its distinctly filmy appearance, while the 

 shape of the leaves approximates somewhat to 

 the general character of the leaves of many liver- 

 worts. And the same remarks apply with still 

 greater force to a beautiful large-leaved moss, 

 known as the Shining Hookeria (Pterygophyllum 

 lucens), which may sometimes be found growing 

 in the shadiest parts of a wood, preferably on 

 the banks of a stream, where it may get an 

 abundance of the moisture that it loves so well. 

 These are, however, exceptional cases, and are 

 therefore not likely to cause much difficulty, 

 even to a novice in the study. 



