LICHENOLOGY OF ICELAND 185 
for instance Hélasandr (north of Myvatn), the “Sanders” in the delta 
of the Jökulsä (at the head of Axarfjörör), and the dunes between 
Myvatn and the Jökulsä. 
The first of these tracts (Hölasandr) consists of black sand, in 
which are numerous stones with worn edges. It is very poor in 
vegetation; there occurred however, scattered uniformly over the 
entire surface, some grass, in tufts, at stated intervals of about !/3— 
1/2 metre. All other kind of vegetation was absent, for instance — 
owing to the strong sand-drifts prevailing everywhere — not a single 
moss or lichen was found. 
As mentioned above, the stones were highly worn by the action 
of sand, and bore no mosses and hardly any lichens; scarcely a 
hundred out of the thousands of stones I passed by during a two- 
hours’ ride, bore any vegetation at all, and even that of these few 
stones was extremely scanty. The following species were found: — 
Stereocaulon spp. (fruticose lichen). 
Parmelia lanata (foliaceous lichen). 
Gyrophora arctica — 
— erosa — 
Lecidea pantherina (crustaceous lichen). 
The dune terrain east of Myvatn bore in numerous places a 
scattered vegetation of Elymus arenarius, which looked very remark- 
able against the dark background of black sand. Here also strong 
sand-drifts prevailed, and the ground was, in consequence, quite 
devoid of lichens. 
As regards their vegetation and other external conditions, the 
blown-sand areas in the delta at the mouth of the Jökulsä, greatly 
resemble, for instance, Hölasandr. The sand, which is mixed with 
stones with worn edges, drifts very much. In stormy weather it 
was not possible for us to see even a few hundred metres in front 
of us on account of the sand-clouds, which filled the air near the 
ground. 
In this place, a little grass, some Silene acaulis, and a few 
other phanerogams, formed an extremely poor and scattered vege- 
tation. Mosses and lichens were totally absent, on account of the 
drifting sand. 
Desert-like, clayey-flats with a poor or scattered vegetation, 
have been described more fully by Jonsson from East Iceland, 
Snæfellsnæs and South Iceland. They are, however, frequently more 
luxurious, and can bear a vegetation which forms a kind of transi- 
