The Botany of Iceland - 01.12.1945, Page 40

382
STEINDÓR STEINDÓRSSON
features of the flói vegetation, so their descriptions cannot be expected
to differ very much. J ó n s s o n, however, points out that the flói need
not be flooded by water all the year round, which view I fully endorse.
Often a marked flói vegetation is found in places where the soil is only
inundated part of the year, especially where there is a constant snow-
covering all the winter. Thoroddsen and to some extent S t e-
f á n s s on state that a number of pools are found in the flói all the
year round. I cannot accept this as a common feature, and I do not
agree with those authors, either, who maintain that the flói vegetation
is very open ; “less continuous than in mýri” (Thoroddsen) might
apply to it, whereas “the vegetation very scattered” (M 01 h o 1 m
H a n s e n) is quite misleading if applied to the flói vegetation in
general.
Helgi Jónsson’s statement (1900, p. 21), that “the plant-
covering... proves to be intersected by many water or mud grooves,
and water or mud pools occur also, which are either irregularly scat-
tered or arranged in rows, whose direction coincides with that of the
grooves” (translated from the Danish), as far as I have been able to
observe, only applies to places where the flói vegetation is at an unstable
stage, that is to say, where it is either being formed, owing to the filling
up of a lake, or it is degenerating owing to an increased water supply.
Thus I have observed this phenomenon in Kýlingar; here the flói area
is repeatedly flooded by the river Tungnaá in the course of the year,
and here the aforementioned pools and grooves are fairly well de-
veloped.
Quite naturally the early authors described the flói as it occurs in
the lowland. I assume, however, that Molholm Hansen’s and
T h or o d d s e n’s descriptions should be considered to be generally valid,
both as regards the lowland and the highland. It is not possible, either,
to demonstrate any great difference between the lowland flói and the
alpine flói. In regard to the surface conditions and the moisture there
is no difference, whereas there must be some difference in the nature
of the soil, for in the lowland a considerable peat-formation is always
going on in the flói, while in the highland it is inconsiderable and the
soil is often very sandy, in some cases perhaps consisting for the greater
part of sand. The composition of species shows some difference also.
The alpine flói is generally still poorer in species than the lowland flói.
This was observed already by Stefánsson, who says (1894, p.
202) : “... on the whole this highland bog vegetation [Eriophorum
bogs and Carex rostrata bogs] is extremely poor in species” (translated
from the Danish).