83 
and American botanists, made a tour through the greater part 
of the British Isles during the summer of 1911. I he tour was 
under the auspices of the British Vegetation Committee. Herr 
Drude’s criticism on the British Flora in contrast with that 
of Germany was that, although it possesses but few indigenous 
plants which do not also belong to the German Flora, yet it is 
a very interesting one, for it represents the Flora of Germany 
at the close of the Baltic Ice Age, when the British Isles still 
formed part of the Continent and, consequently, shared its 
vegetation. x 4 fter the separation had taken place and the British 
Islands had been formed their distance from the mainland had 
this effect on their Flora, that it remained purer than that of 
Germany which was so exposed to extraneous influences as to be 
much modified and altered by them. Examples of the survival of 
this very ancient Flora in all its integrity are not wanting, but are 
scattered here and there over our islands. For instance the shore 
of the Bay of Galway is covered with the shrubby Potentilla 
which is also a native of Germany and of Central Europe. Herr 
Drude in fact states it as his opinion that in modern times the con¬ 
ditions of vegetation over the larger portion of the British Isles 
are so uniform as to furnish the conditions for the development 
of characteristic forms in their somewhat extensive area from the 
general stock of the west and north European Flora which has 
been present or invaded these islands since the Ice Age. At least 
on the lower hills up to a height of about 100 metres a uniformity 
is apparent markedly differing from what we find in mid Germany 
in the English, Scottish, and to some extent also in the Irish 
Flora. The woods of the south and east English vegetation 
region show a striking deficiency as compared with those of the 
Ge rman plains and hills in the absence of Pinas sylvestris. This 
tree though very abundant on sandy soils is not generally re¬ 
garded as a native in the south-east of England, though it was 
apparently general in early post glacial times. It owes its pre¬ 
valence in some of the New Forest heaths to its introduction into 
Ocknell Clump in 1776, though there is some evidence of its 
much earlier occurrence in the district. In a general way the 
trees and shrubs of the British Islands offer a great difference 
from those of Germany. Our woods and coppices do not present 
the same variety as the German. In England there is lacking 
that delightful mixture of various trees offered b}' a mid German 
valley, where behind Alders ( Alnus glutinosa , Alnus incana ) absent 
from England, Carpinus Be talus (Hornbeam) is mixed with Acer 
platanoides (Norway Maple), Ulmus (Elm), Tilia (Lime) and 
others 011 the valley sides, giving place to Beechwoods with Picea 
and Abies , and making way for Pinas sylvestris (Scotch Pine) on 
the steeper and drier slopes. On the other hand our Heathlands, 
more especially those of the New Forest apparently possess a 
richer and more beautiful Flora than those of mid Germany. 
Erica Tetralix, Narthecium (Bog Asphodel) and Hypericum Elocles 
(Marsh St. John’s Wort), the masses of which adorn our heaths are 
