MOORLAND AND ALPINE PLANTS 391 



Cotton-grass moors. A large part of the Pennine plateau 

 is covered with deep, very wet, acid peat, which contains 

 much organic matter and is very poor in mineral salts. It is 

 composed of the remains of previous generations of Cotton- 

 grass and other moorland plants, and, in places, of Bog-moss 

 and Hair-moss, while buried at the base of it are numerous 

 remains of Birch and other trees. Growing on this is a 

 monotonous stretch, many miles in extent, of closely packed 

 ' tussocks ' or ' hassocks ' of the Cotton-grass ; its growth 

 being favoured by a high rainfall of 45 inches or more. 

 Locally these Cotton-grass areas are called ' mosses ', and 

 very many place-names are derived from them. 



Very few other plants are found here ; the chief are the 

 Cloudberry, Crowberry (Fig. 253, 1), and Bilberry (Fig. 254, 

 1). Here and there are patches of Bog-moss, growing over 

 which are the slender branches of the Cranberry (Fig. 254, 3). 

 Two species of Cotton-grass are met with. One, by far 

 the more abundant (Fig. 250), has narrow leaves per- 

 meated by two rows of large air-channels (Fig. 255, 6), and 

 when in fruit, bears a single cottony tassel. The other kind, 

 often confined to wet channels or hollows, has broader leaves 

 and large air-spaces (Fig. 255, 5), and bears several cottony 

 tassels on its fruiting shoot (Fig. 158, 1). The stomata 

 in both species are on the exposed surfaces ; and this 

 feature, together with the large air-channels, recalls struc- 

 tures we have met with in water-plants. Another point 

 of comparison is that the Cotton-grasses grow in a wet, 

 badly aerated soil, very rich in organic matter. 



At the edges of the Cotton-grass moors, where drainage is 

 better and the peat drier and shallower, the Cotton-grasses 

 are replaced by Bilberry (Vaccinium Myrtillns), and with it, 

 but growing less abundantly, are Cowberry (V. Vitis-Idaea), 

 Crowberry (Empetrum nigrum), and other heath-plants. 

 Often long Bilberry edges thus arise (Fig. 252). On the 

 steeper, more sheltered slopes, extensive stretches of 



