163 
ably smaller on the stony flats at Vassijaure than in the 
lowlands, often only half as large, but comparatively broader. 
A somewhat similar effect may be observed in other Arctic 
regions, but it should be remembered that the development of 
the leaves is, to a very great extent, dependent upon the nature 
of the habitat, and that small, poorly developed leaves can as 
well occur on Danish heaths as on those in Arctic regions; 
or vice-versa, the leaves may be as well developed on Disko, 
for example, as in Denmark. 
Towards the apex of the shoots the leaves are very close-set. 
There is no other protection for the young leaf-rudiments than 
this dense crowding of the leaves.! 
As is well-known, the leaves expand long after the flowering 
of the plant; in Denmark, in April or early in May, but in 
the Arctic regions naturally much later still; thus as regards 
Greenland the leaves do not expand until some time in July 
(this statement is based on the material to hand; I have in 
vain searched in the literature upon the subject for information 
regarding the leaf-expansion). As a result, the shoots have 
only a very short time in which to grow, for during September, 
without doubt, all growth is stopped. It will easily be under- 
stood that, as mentioned above, the growth-increment can on 
the whole be but small. 
In connection with the fact that the leaves are evergreen, 
is their xerophylic nature; their peculiar structure is described 
by several authors, as GiBELLı, Gruser, Warning, Borcesen (3), 
Wasser (18), etc. The notes by Warne (20) and Börszser (3) 
on this subject are particularly interesting, because their 
investigations were carried out upon Arctic material; otherwise, 
7 ENGLER (Die natürl. Planzenfam. Ill, 5, p. 127) says: — ‘‘Knospen- 
schuppen lang bewimpert.” But we cannot be justified in talking of 
budscales proper, although it is true that the leaves, when quite young, 
are furnished with long hairs, which are matted together very densely 
in the space above the shoot-apex; this may easily be ascertained by 
a median section through the apex of the shoot. 
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