The Botany of Iceland - 01.12.1930, Side 88

78
H.M0LHOLM HANSEN
centages, while the A 1 species are practically absent. In the E sub-
groups the peculiarity appears in the fact that the decrease comes
especially under E 2 and likewise in no small degree under the E 4
species, while the E 3 percentage is considerably higher than in the
surrounding tj'pes of vegetation, mo and jaðar or mýri. Both the
locaiities examined, tlie south country as well as the norlh country,
show the same deviation from the adjacent types of vegetation with
regard to the species group spectra. The flag vegetation is thus
characterised by comparatively high A 3, A 2, and E3
percentages, and by comparatively low A 1, E 4, and E2
percentages.
As regards the distribution of the flag vegetation it may be said
that in Iceland it seems to be peculiar to the lowlands alone. Per-
sonally I have sought the flag vegetation in vain in the liighland
tracts of South Iceland (Lýngdalsheiði), of Arnarvatnsheiði and Holta-
vörðuheiði (Tvidagra). Magister Pálmi Hannesson, who has ex-
plored the highlands for a number of years, lias informed me orally
that a flag vegetation has never been observed here. Helgi Jóns-
son refers the clayey flats (i. e. the flag vegetation) to the “open
vegetation of the lowlands” (it is not mentioned that they only occur
in tlie lowlands). If we may infer from this that the clayey flats have
not been seen bj' Helgi Jónsson in the highlands, all observations
would seem to indicate that the flag vegetation is limited to the lowlands.
In Iceland the flag vegetation has been observed in all parts
of the country. As mentioned above, H. Jónsson has described it
from East Iceland, South Iceland, and South-West Iceland. On my
journey in the summer of 1925 I observed flag vegetation in the
south country (at the foot of Ljmgdalsheiði) in the south-west countrj'
(Norðtunga in Borgarfjörður), and in tlie north country (Lækjamót
in Viðidalur). According to the oral communication of Mr. Jacob
Lindal, the farmer at Lækjamót, who has travelled through the
north country as consulting agriculturalist for a number of years,
tlie flag vegetation is of common occurrence throughout this part.
Judging from the literature, the flag vegetation seems to be
peculiar to Iceland. I have not been able to find in the phyto-
geographical literature on the surrounding countries any record of
types of vegetation which may be compared with or referred to
the flag vegetation in its typical form.
Hence the flag vegetation seems to be a type of ve-
getation peculiar to the Icelandic lowlands.