246 
Oscar Drude. 
Sesleria, Calluna, Erica and Empetrum. Higher up it occurs with 
Rubia peregrina and Arctostaphylos Uva-ursi; and at 200 m., in the 
clefts of the hard limestone, with Scolopendriuin, Adiantum Capillus- 
venevis (rare), and Habenaria Intacta in part of its “ limited and 
probably continuous range along the western edge of the Limestone 
Plain from Burren to Cong ” (Praeger, op. cit.). I know of no 
similar example in the German and north Alpine Flora of so perverse 
a distribution and mixture of relict-stations. 
The Structure of the Plant-Formations. 
It appears to me natural, in all detailed work, at least on the 
formations of dry ground, to maintain the threefold division of the 
British Isles into the formations of southern and eastern England, 
those of Scotland, including the siliceous mountains of northern 
England over 250 m. (or at least over 1000 English feet), and finally 
those of Ireland and Cornwall. 1 Wales probably shares in the 
character of all three of these divisions, hut we had no opportunity 
of seeing this highly interesting country. 
It is necessary to premise that only the first of these divisions 
can be usefully compared with mid-Europe (Germany including the 
northern Alps). The north of Great Britain must be compared 
with Scandinavia and the Faroes, the west of Ireland and Cornwall 
with the north-western French peninsula (Brittany) and with the 
Asturias, etc. 
Woodland, Scrub, etc., in Southern England. 
The woods of the south and east English region show at once 
a striking deficiency as compared with those of the German plains 
and hills in the absence of Pinus silvestris. This tree, though very 
abundant on sandy soils, is not generally regarded as native in the 
south-east, though it was apparently general in early post-glacial 
times. 2 In the counties which I saw the oak and the ash, on the 
southern chalk the beech (with yew), and on the higher siliceous 
hills the birch (the oak scarcely ascends beyond 300 m.), especially 
B. pubescens (which, as compared with Germany, takes a relatively 
prominent position), were practically the only dominant trees, where 
1 Fagus silvatica (characteristic of south east England) is never¬ 
theless recorded as wild in Cornwall, while in Ireland, as is 
well-known, it is absent. 
2 See “The Woodlands of England ” by Moss, Rankin and Tansley, 
New Phytologist, IX, 1910. The possibility, however, of 
the nativity of Pinus in the south-east of England is there 
suggested, p. 134. 
