The Botany of Iceland - 01.12.1945, Blaðsíða 113

THE VEGETATION OF CENTRAL ICELAND
455
typical Grimmia heath.
Analysis XVIII, i was 3 4
made near Laugar at
Snæfell, and analyses ''-{/ÁU////l//k^~
XVIII, 3-4 in the hills ((^^//l/i/hri^-
east of Eyjabakkar. In
all these localities the
Grimmia heath is stony
and the soil damper
than is usual in this
formation. In these
places Cetraria is very
conspicuous in the
Grimmia heath, and
in analyses 3-4 Cassiope
hypnoides is so abund-
ant that we might speak
of a Cassiope variant.
Jónsson (1895, p.
71) points out that in
eastern Iceland Cetra-
ria is abundant in the
Grimmia heath. Possibly this Grimmia heath rich in Cetraria is a
formation which is specific for eastem Iceland. At any rate it is
not recorded from other places. Compared with other localities for
Grimmia heath the variant rich in Cetraria is always found where the
soil is dampest. Analysis XVIII, 2 is from Eyjafell. The Grimmia is
here highly mixed with other mosses, though it dominates among them.
The sketch in Fig. 10 shows the position of different formations in
relation to each other in the hills east of Eyjabakkar. The lowest-lying
is a nearly circular grassy plain which is probably flooded by thaw-
water in the spring. Then follow zones with different formations, and
at the top of the hill a gravel flat.
Analyses XVIII, 7-8 were made on Síðumannaafrjettur at an alti-
tude of c. 400 m. The soil is rather damp. It would seem that on
Síðumannaafrjettur the Carex rigida association disappears between
500 and 600 m altitude. Analysis XVIII, 6 was taken at an altitude
of c. 600 m; here C. rigida has disappeared, while it occurred on the
same mountain side at a somewhat lower level. In analysis XVIII, 7
Vaccinium uliginosum is so abundant that we might speak of a variant
Fig. 10. The situation of some plant communities
in the vicinity of Eyjabakkar. 1, Calamagrostis
neglecta-Assoc.; 2, Association rich in mosses,
with scattered patches of Carex rigida and Salix
herbacea; 3, Moss heath with scattered patches of
Cetraria (Tab. XVII. 10); 4, Melur
(Tab. XXI. 8).