24, MOSSES AND LIVERWORTS 



its flat growth; the CEder's Apple-moss (Bar- 

 tramia (Ederi), with its small, round, apple-like 

 spore-vessel; the Tall Anomodon (Anomodon 

 viticulosus] ; and the Star-leaved Thyme Thread- 

 moss (Mnium stellare\ are all instances, among 

 many that could be quoted, of mosses that have 

 a distinct preference for calcareous districts. On 

 the other hand, the plant given at Plate II. 

 fig. 5, the Yew-leaved Mat Pork-moss (Fissidens 

 taxifolius), is equally partial to a heavy soil, 

 such as marl or clay. This moss is a member 

 of a small family, represented by some fifteen 

 British individuals, all of which have a very 

 strong family resemblance, and are, from their 

 peculiar mode of growth, always easily known. 

 It will be seen from the drawing that the plant 

 has a markedly flat appearance, all the leaves 

 being arranged on the stem on the same plane. 

 And on looking closer still it will be found that 

 each leaf -blade (lamina} is, for about a quarter 

 of its surface, double, as though a tiny flange had 

 been fastened to the mid-rib or nerve, the stem 

 itself passing between these two leafy surfaces. 

 This is more clearly shown at fig. 19 of Plate VII., 

 which represents a leaf drawn to a larger scale. 

 The shaded portions in this and the previous 

 drawing indicate these double parts, the increased 

 thickness rendering them somewhat more opaque. 

 The Pointed-leaved Weisia (Weisia mucronata, 

 Plate II. fig. 16), with its tapering and pointed 



