The Botany of Iceland - 01.12.1930, Side 110

100
H. M0LHOLM HANSEN
see, the following species were exclusively associated with this ve-
getation: Taraxacum laevigatum, Epilobium anagallidifolium, Carex
lagopina, Gnaphalium supinum, Pirola minor.” “Of the two dominant
species, Salix herbacea and Sibbaldia procumbens, Salix herbacea is
found in tlie greatest proportion. They either occur as separate
dominants, or they dominate together intermixed with one another,
and then either in equal number or with preponderance of the one
or the other.”
V. The Philonotis fontana Dý. “On damp gravel and at
small springs small cushions of Philonotis fontana occur. In these
light-green cushions of moss some flowering plant is generally met
with, Cerastium trigynum and Saxifraga rivularis especially show a
predilection for these spots. These moss cushions correspond to
the dý occurring at lower levels.”
The second type of vegetation which H. Jónsson distinguishes
is that of rock pools. 1900, p. 20 he writes: “Up the mountains,
tliough not at very high levels, there occurs a characteristic vege-
tation met with near pools, the vegetation of the rock pools; these
pools are especially Eriophorum pools where E. angustifolium is
solely predominant. They are extremely poor in species, yet we
may mention the occurrence of scattered Carex rostrata, C. pulla,
and C. alpina.”
The third tvpe of vegetation is the Grimmia heath. We have
previously dealt with this vegetation (p. 40) with the main result
that it belonged to the higher regions of the country to the south
and east of the jökull line. It was most abundantly developed in
the foggy and rainy regions of East Iceland, decreasing to the
westward, and being absent in the north. “In the lowlands and at
the lower levels of the m ou n tains it changes in time and gives
place to other plant societies; as a rule many phanerogams and
vascular cryptogams are intermixed with it. Tliese decrease con-
siderably with increasing height above the sea, and have almost
entirely disappeared from the Grimmia heath of the highest levels
(at c. 600—700 m.); there only solitary, very widely scattered, com-
mon fell-field plants are met with.”
A comparison shows a great, but probably more apparent than
real, difierence between the vegetation schemata of the two autliors.
Stefánsson describes the following types: melar, mo, mýri, and
snow-patch, Helgi Jónsson: fell-field (with sub-divisions gravellj
flats, screes, the Anthelia crust, the Salix herbacea and Sibbaldia