23B 
Oscar Drude. 
verrucosaX How much we learned even on the first day at Cambridge 
from Dr. Moss in his interesting demonstrations of the South 
English forms of Ulmus. 
To bring these fragmentary remarks to a conclusion, I may say 
that I gained the impression of numerous slightly differentiated 
local forms, endemic in England, and I think the study of such local 
forms can scarcely be satisfactorily developed in the herbarium, but 
belongs rather to the local floras of geographically and ecologically 
separate regions. (Enanthe fiuviatilis Colem. which we saw so well 
in the River Cam, is given in Druce’s List as an “endemic” species 
for thirty-one British and two Irish counties. If the same form 
occurs also in south-west Germany, the fact indicates that analogous 
ecological conditions have led to analogous “ races ” rather than 
that the same race has such a discontinuous distribution ; and one 
may expect the identity of the forms to be incomplete. 
Uniform Floristic Distribution in the British Isles. 
The question arises if the conditions 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 this not 
inconsiderable area from the general stock of the west and north 
European flora which has been present in or has invaded the country 
since the Ice Age. I am inclined to answer this question in the 
affirmative in spite of the fact that Great Britain falls into a series 
of well-marked floristic regions. 1 At least on the lower hills, up to 
a height of about 100 m., there is apparent a uniformity, markedly 
differing from what we find in Mid-Germany, in the English and 
Scottish, and to some extent also in the Irish flora. Thus we find 
the same species distributed throughout the whole country to a much 
greater extent than we should expect over a range of nine degrees 
of latitude. And the cultivated areas, from the south of England 
to the valleys of the Grampians, contain species, whose growth is 
1 Thus there are the warm south-east of England with beechwoods 
on the slopes of the “Downs”; the east, drained by the 
rivers Ouse, Cam and Nene, with only 55 cm. of annual rain¬ 
fall and a more continental climate ; the Atlantic south-west 
(Cornwall) ; the similarly situated part of Ireland, which has, 
however, higher mountains; the limestone region of the north 
of England, in which Sesleria casnilea occurs in spite of its 
curious absence from the south ; and the fine mountain regions, 
differing from one another in many respects, with summits up 
toandexceeding 1000 m., from Glamorgan northwards through 
Wales (which we unfortunately could not visit), the Pennines, 
the mountains of Westmoreland and Cumberland, and finally 
the crown of all, the Grampians, which formed the northern 
limit of our tour. 
