194 OLAF GALL@E 
As examples of lichen-vegetation in grass-carpets, I shall men- 
tion a few observations which are typical: — 
On sloping ground on the sides of Reydarfjöröur (East Iceland) 
heaths and grass-carpets grow mixed with one another. The latter, 
seen from a distance, have a light greyish-green colour and consist 
mainly of Festuca ovina mixed with a small amount of Calluna, 
Empetrum, Dryas, Silene acaulis, Cassiope hypnoides, Betula nana, 
some mosses and Lycopodium. When I visited the place the grass 
was very short (3—6 centimetres), being closely grazed by sheep 
whose dung was found everywhere. Here and there was an ex- 
tremely small number of lichens, which played a very subordinate 
part both as regards abundance and degree of frequency. 
The degree of frequency was determined neither here nor in 
any other of the grass-carpets investigated by me, because the 
lichens were so exceedingly unevenly distributed that, in order to 
obtain a fairly reliable frequency-number, a far larger number of 
sample-areas would be required, than I had time to investigate. 
The following species were found: — 
Stereocaulon coralloides. Cladonia fimbriata. 
— tomentosum f. cam- Thamnolia vermicularis. 
pestre. Cetraria aculeata. 
= incrustatum. Peltigera canina. 
Cladonia pityrea. — aphtosa. 
— uncialis. Bacidia flavo-virescens. 
In quite similar localities, and in an exactly similar vegetation, 
I found near Seydisfjöröur the same scanty lichen-vegetation sup- 
plemented by a few other species, viz. 
Psoroma hypnorum. 
Dermatocarpon hepaticum. 
Collema spp. 
I found on extensive, very knolly grassland, on mountain-slopes 
on each side of Eyjafjöröur, a somewhat different vegetation, in that 
the top of the knolls bore Dryas, Betula nana or Empetrum — an 
indication of heath-vegetation. Upon these dwarf-shrubs and the 
dead portions of the grass-tufts on the top of the knolls, occurred 
masses of Lecanora tartarea, and here and there a solitary Cetraria 
aculeata. The former crustaceous lichen is, as is well-known, ex- 
tremely common on the stunted plant-carpets of the Arctic regions, 
for instance in Lapland and Greenland. 
I found near Eyjafjöröur, just below the summit of Sulur- 
