136 C. E. Moss , W. M. Rankin and A. G. Tansley. 
( Cratcegus monogyna) and sallows (Salix caprcea and 6'. cinerea) are 
often abundant. Holly ( Ilex Aquifoliuin) occurs, but rarely flowers 
or fruits. Upland forms of Rosa and Rubus are found, and are 
sometimes abundant; while ivy ( Hedem Helix ) and honeysuckle 
(Lonicera Periclymenum) are locally very plentiful. 
The ground-vegetation resembles either that of the adjoining 
grasslands or of the adjoining moorlands. In the former case, heath- 
loving grasses such as Aim flexuosa form a springy turf. Scattered 
among the grasses are Galium saxatile, Carex binervis, C. pilulifera, 
Potentilla erecta , and upland Bryophytes. The bracken ( Pteris 
aquilina) sometimes occurs in extensive sheets, and at other places 
is less abundant or even quite absent. In the woods with a ground 
vegetation made up of moorland under-shrubs, which often almost 
entirely clothe the ground, heather ( Calluna vulgaris) and bilberry 
(Vaccinium Myrtillus) are the most abundant and characteristic 
species. The relative frequency of the two species is determined 
to some extent by the shade cast by the leaves of the shrubs and 
trees overhead; for the bilberry invariably penetrates into more 
shady portions of the wood than the ling or heather. Locally, the 
cowberry ( Vaccinium Vitis-Idcea) is abundant, and Molinia ccerulea 
occurs amongst the under-shrubs. Mosses and liverworts are 
abundant, especially Sphagnum spp., Polytrichum commune, Campy- 
lopns JlexHosus, Dicranum scoparium, Aulacomnium palustrc, Wcbera 
nutans, Hypnnm spp., Lepidozia rcptans, and Nardia scalaris. 
It will be seen that the ground vegetation of the upland birch 
woods of the north of England has much in common with that of 
the oak-birch-heath association of the south, but that it contains 
many elements indicating the damper conditions. 
Several rare species of flowering plants which are found in the old 
birchwoods and pinewoods of Scotland fail to reach so far south as 
northern England. Corallorhiza trifida stops at the Border: 
Goodyera repens practically stops in Cumberland, but has outlying 
stations in east Yorkshire and Norfolk: Linncea borealis and Pyrola 
secunda are rare in northern England; while P. uniflora is unknown 
there. Listera cordata and Trientalis europcea, which occur in the 
Scottish birchwoods, exist on the Pennines as moorland plants 
only ; and even on the moors, they are rare and local. Pyrola media 
and P. minor appear, in fact, to be the only species of this class 
which are typical both of the Scottish birchwoods and of those south 
of the Border country; and even these species are rare and local 
throughout the whole of England. 
