228 OLAF GALLOE 
ture on the subject, I have not found any allusion made to anything 
of the kind. 
d. Liparite. 
This rock is not widely distributed in Iceland, and therefore 
plays a very inferior part in the physiognomy of the country. In 
chemical respects it is of the same composition as granite, since it 
is the corresponding volcanic rock. 
I have only had an opportunity of investigating its vegetation 
in very few localities, viz., in Hlidarfjall, near the farm Reykjahliô, 
close to Myvatn, and near Geysir. I am therefore not prepared to 
state anything about the vegetation it supports, when it stands in 
salt water, nor what the conditions on it may possibly be, when 
we find it as a lofty mountain. 
Near Geysir, on the mountain situated close to the spring itself, 
I found a very scanty vegetation consisting of crustaceous lichens 
(F °/o 100), a few foliaceous lichens (F °/o 36) and a little moss (F °/o 
16). The mountain was far from being covered, consequently, the 
vegetation was desert-like, and all the specimens were small, and 
only slightly developed. The following species were found: — 
Lecanora pallescens, crustaceous lichen. 
> varia — 
Lecidea auriculata, — 
Sterile, undeterminable, — 
Rhizocarpon geographicum, — 
Gyrophora erosa, foliaceous lichen. 
55 cylindrica, : — 
On Hlidarfjall near Myvatn, at the base of a solitary mountain- 
summit, which rises above the surrounding country, there is a 
mighty talus of large fallen blocks, and of débris. Upon the blocks, 
and upon the mountain itself, there occurred a scanty vegetation — 
open and desert-like — of various foliaceous and crustaceous lichens. 
The following species were found: — 
Lecanora polytropa, crustaceous lichen. 
= (Aspicilia) alpina, = 
= impavida, = 
Rhizocarpon geographicum, = 
Parmelia lanata, foliaceous lichen. 
Gyrophora erosa, — 
— cylindrica, — 
