252 
Oscar Drude. 
at 800 m. Saxifraga stellaris, at 900 m. Lnzula spicata and Sibbaldia, 
at 950 m. Carex saxatilis (with Beilis perennis and Chrysosplenium ); 
and above 1000 m. the pure arctic-boreal associations, are found 
i.e., some 500 m. lower than in the Riesengebirge and Bohmerwald. 
On Ben Lawers jfuncus trifidus descends to 900 m.: in corresponding 
places on the Riesengebirge (east slope of the Schneekoppe), where 
it likewise forms closed communities, only to 1420 m. 
Lowland Heaths. 
The lowland heaths, the “ heath association ” or “ Callunetum 
arenosum ” of Tansley, 1 for the most part correspond with those of 
north-western Germany in the region of the Weser and the Erns, 
and on the English heaths one would often feel oneself transported 
to Germany if it were not for the sudden occurrence of Erica cinerea 
between Tetralix and Callnna, or of Ulex minor or Gallii, with 
masses of Schcenus nigricans, Myrica Gale, Narthecium and Hypericum 
Elodes, which indicate the west-European conditions. Especially 
striking is the purely western “ Cornish heath,” Erica vagans, on 
the Lizard peninsula, which is by no means a rarity, but occurs as 
the most important constituent of the whole heath formation in 
that locality. For the rest, Tansley’s remark 2 that “ most of the 
species of south-west European plants for which the Lizard district 
is famous occur on the grassland of the sea cliffs or in their clefts, 
and not on the heaths” is of great interest. 
Aquatic Formations. 
The formations of water-plants, floating and submerged, the 
reedswamps and infra-aquatic fens, and finally the fen woods of 
Alnus, Betulapubescens and Salix cinerea, (with Humuhis^mXLonicera 
as lianes, and luxuriant Osmunda regalis) developed from reedswamp 
^nd fen, with which we became acquainted in the Norfolk Broads 
under the admirable leadership of Miss Marietta Pallis, are so 
interesting that it is impossible to pass them over. The great 
effectiveness of the methods pursued in England and America, which 
direct ecological investigation mainly to the association, and the 
connection or replacement, of groups of species under the stress of 
changing soil conditions, here became especially apparent. 
It seems probable that formations corresponding with those of 
the Norfolk Broads, if not so variously developed or on equivalent 
ground, might be found in the north German plain, perhaps in the 
Spreewald or at Dromling. If so, a comparison would be interesting, 
1 “Types of British Vegetation,” pp. 103 et seq. 
2 “ Types,” p. 110. 
