The Botany of Iceland - 01.12.1930, Page 108

98
H. M0LHOLM HA.N'SKN
opeta, Saliceta (herbacea) and Sibbatdieta in irregular and eonfusing
intermixture. Interspersed among them there are many herbs which
do not belong to the fell lield, especially the herbs ol’ the heather
moor. There is no well-marked limit liere, hut the fell field may
be plainly distinguished by the fact that tlie plants of the heather
moor are not able to form any heatli but grow in palches or as
scattered specimens, and that the small characteristic Saliceta (her-
bacea) and Sibbaldieta of the fell lield liave begun to appear.”
H. Jónsson distinguishes between the following 5 types of vege-
tation in the fell íield: gravelly llats, screes, the Anthelia-crust, the
Salix herbacea and Sibhaldia vegelation, and the Philonotis fontana dý.
I. The gravelly flats. “With the exception of the naked
rocks, the gravelly flats are those parts of the fell-field which are
poorest in vegetation. In the upper part of the fell-field they are
exceedingly poor in plants, especially if they are exposed; in the
lower part of tlie exposed flats often only a solitary Ranunculus
glacialis or a solitary Cerastinm alpinum is met with. On less ex-
posed ílats in the lower part of the fell-field a considerably richer
vegetation is met witli.” In such a locality Salix herbacea and Al-
chemilla alpina occurred in patches, further Armeria, Aira alpina,
Luzula spicata, Oxyria digyna, Cerastium alpinum, Silene acaulis,
Arabis petrœa, Galium silvestre, and Saxifraga cœspitosa.
“On the gravelly flats which are studded with small shelter-
givers, small stones dispersed more or less closely over the flat, we
meet with the richest vegetation which can occur on a gravelly flat
in the fell-field. Round the little stones there occur narrow fringes
of Grimmia hypnoides. In the Grimmia fringes grow the most
frequently occurring plants of the fell-field.
II. The screes. “From the last-mentioned gravelly flats there
occur the smoothest transitions to the screes. When the shelter-
givers, the scattered stones, become larger and occur closer together,
the surface loses the character of a gravelly flat ánd must be re-
garded as a scree with small stones. Here Grimmia hypnoides is the
most important plant, though it does not form heath.” “As regards
the plants intermixed with it, we must distinguish between the upper
and the lower fell-field, or levels above and below 600 m.”
In the upper fell field there is as a rule only an intermixture of
lichens, the phanerogams are poorly represented. “Thus, in the
upper part of the fell-field on Snæfellsnes Jökull at an altitude of
600 m. only the following species were met with: Armeria maritima,