The Flora of Disko Island and Adjacent Coast of West Greenland. 121 
published his ~“Andet Tilleg” to Lance he further reduced groenland- 
cum to a variety coordinate with decumbens and palustre a, cp. p. 691. 
The reduction of L. groenlandicum to a variety is, however, in direct 
opposition to the view of modern American florists and taxonomists. 
Having the profoundest knowledge of the plant from their resear- 
ches in nature, they without any exception classify it as a separate 
species. And, we may add, as all modern dendrologists do, also in 
Europe where the plant still everywhere preserves its different aspect 
under cultivation; (see for instance C. K. Scunemper: “Tllustr. Handb. 
der Laubholzkunde” I]. 1912 p. 469). As will be seen by our investi- 
gations we cannot but support this view. 
Regarding the other Ledum in Greenland | (i.e. M. P. P.) cannot 
see but one taxonomic unit init. I must confess that its variations 
on favourable habitats tend to develop larger leaves, but on the other 
hand I never found plants like typical specimens of L. palustre from 
Northern Europe. There always remains a certain characteristic habit 
giving it a different appearance. And as the geographical features 
seemed to support my view of L. decumbens as specific distinct from 
L. palustre, a closer investigation of a large material became desirable. 
As our home in Greenland is situated far to the north of the area of 
L. groenlandicum and as our material of herbal specimens of this species 
and still more of L. palustre, was too scanty, we applied to the Trustees 
of the Botanical Museum at Copenhagen and obtained a large material. 
As form and size of the leaves hitherto yielded the most conspicuous 
distinguishing characters, an investigation of those points was chosen 
as our main object, the more so because time was scarce, the printing 
of our M. S. had been begun. This investigation was carried out by 
E. P. alone. 
The distinguishing characters of Ledum palustre, L. decum- 
bens and L. groenlandicum. (By A. E. P.) 
In order to ascertain the size and form of the leaves of Ledum 
| investigated the material preserved in the herbariums of the Arctic 
Station in Greenland and of the Botanical Museum at Copenhagen. 
For the great majority of specimens I took the determinations, as they 
were left by the several collectors, only of a shght number of specimens 
have I altered the determinations, after having found a new distinguish- 
ing character (see below). For the investigation a well developed 
year’s shoot of every specimen was taken and the leaves were measu- 
red: the length without the petiole, the breadth without the 
