196 VEGETATION OF THE PEAK DISTRICT (oe 
34, c) is developed. The plateaux of the cotton-grass moor 
either descend gradually into the zone of upland cultivation 
(figures 33 and 34, e), in which case these two zones are 
separated by a zone of heather moor (figures 33 and 34, d) ; 
or they are terminated abruptly by steep shaly slopes, in which 
case the zones of cotton-grass moor and upland cultivation are 
separated by a zone of Nardus grassland (figures 33 and 34, d). 
The relationships of the plant formation of the siliceous soils 
and that of the moors may be seen in the following table :— 
Sub-Alpine, Grassland 
Bare Peat 
Patani: Ridges 8 
; EH) 
Retrogressive Moors AS 
b 
OxopI0N Cotton-grass Moors 8 
ra 
Heather Moors 
Nardus Grassland Molinia ‘Grassland 
with much Heather 
Nardus Grassland Birch Woods (B. pubescens) 
SILICION 
Scrub 
\ Oak Woods (Q. sessiliflora) 
List OF SPECIES OF THE Moor FORMATION 
The following species occur on the moor formation (ef. 
Ostenfeld, 1908: 947 et 956) of the southern Pennines; and 
their relative frequency in the three chief associations is also 
indicated. The plants preceded by an obelisk have not been 
recorded from the Peak District; but they occur a few miles to 
the north. 
