IIAI'.ITATS OF MOSSES. 33 



tudcs, except in high latitudes. Other things being equal, the 

 zones of Mosses in a given locality, on a high mountain, are 

 as capable of accurate definition as those of Phsenogams. In 

 tropical climates a favourite situation of many delicate species 

 is the thick coriaceous leaves which are so common there, and 

 so persistent; and even in our own climate, a Moss may now 

 and then occur on evergreen leaves, but then only by accident. 

 The different nature of soil also, whether from its mechanical 

 division or chemical composition, has a considerable influence 

 on the production of species. The hard beaten sides of foot- 

 paths, the loose crumbling matter at the base of rocks, the 

 sand by the seashore, the rich moist banks of ditches, the 

 grassy meadow, the naked clay, the deep recesses of woods, 

 the peaty soil of heaths and moors, the damp margins of 

 pools or swamps, and wet boggy ground, have their own ap- 

 propriate species, not to mention the variety of Mosses which 

 are more truly aguatic, whether in rapid streams or quiet 

 waters. The mud-capped walls which are so frequent in 

 oolitic districts produce always a multitude of species, some of 

 them of rare occurrence elsewhere, while the little mounds 

 made by ants are sometimes extremely productive. The 

 Phasca seem to luxuriate especially in fallow fields where the 

 soil is thin and not retentive of moisture, especially in cal- 

 careous districts. Within a square yard half-a-dozen species 

 may sometimes be found where these conditions exist. Though 

 at a moderate distance from the sea a variety of species 

 may occasionally be found in great perfection, there are very 

 few which, like Schistidiwn maritimum, choose by preference 

 situations constantly exposed to the spray of salt water. 



