THE ECOLOGY OP PLANTS. 427 



and stems of the Cotton Sedge contain air-spaces communi- 

 cating with the rhizomes and roots. In extreme cases the 

 vegetation of the Cotton Sedge Moor is very scanty, only a 

 few mosses, liverworts, lichens, and small fungi occurring on 

 the peat between the Cotton Sedge plants. In wet weather 

 the moor is a soaking mass with pools between the tufts of 

 Cotton Sedge and soft peat-banks fringing the numerous 

 water-courses. The Bog-mosses occur chiefly in patches and 

 their remains are seldom abundant in the peat itself, which is 

 chiefly composed of the remains of Cotton Sedge. At the edges 

 of the Cotton Sedge Moor the dominance of the characteristic 

 plant is shared by Ling and Cross-leaved Heath, the former in 

 drier and the latter in wetter places. Other associated plants 

 are Bilberry, Cowberry, and Crowberry, the Bilberry often 

 covering the more exposed rocky summits and ridges. 



The Heather Moor is drier than the Cotton Sedge Moor, 

 and therefore has a greater variety of plants, though the 

 Ling itself often grows knee-deep and so thickly as to allow 

 of very few associate-plants. The typical Heather Moor is 

 developed at 1000 to 1500 feet, on the drier or steeper sides 

 of the moors, and is brown in winter and green in summer, 

 but purple in autumn when the Ling itself is in flower. The 

 peat is thin from three or four to a few inches. The most 

 important of the sub-dominant plants are Bilberry, Cowberry, 

 Cross-leaved and Bell Heaths, Dwarf G-orse, Bushes, Mat- 

 grass (Nardus), Wavy Hair-grass {Air a flexuosa), and 

 Bracken, and almost any of these may become dominant over 

 a considerable area Bilberry on dry edges and summits, 

 Bracken on steep stream-banks, and so on. 



Other plants often present are Tormentil, Heath Bedstraw, 

 Sorrel Dock, Field Woodrush, Sedges, Bent-grass (Agrostis), 

 Purple Bent- grass (Molinia), and other plants, mostly small 

 and wiry with creeping stems. The taller rushes (Juncus) 

 form distinct associations in the swampy basin and beside 

 springs the larger Juncus marshes are indicated on the six- 

 inch Ordnance map (Art. 420). Along with the Eushes grow 

 such plants as Ivy-leaved Crowfoot, Bog Stitchwort, Blinks, 

 Marsh Cinquefoil, Marsh Pennywort (Hydrocotyle), Sundew, 

 Marsh Bedstraw, Lousewort, Butterwort, Bog Asphodel, 

 Pond weeds (Potamogeton), etc. Cotton Sedge also occurs, 

 here and there on the Heather Moor. 



