The Botany of Iceland - 01.12.1949, Síða 9

THE FLORA OF RF.YKJANES PENINSULA
7
Reykjanes peninsula has practically no running waters owing
to its vast porous postglacial lava fields, which cannot keep the rain
water on the surface; the water is running through subterraneous drains
straight to the sea. Only in “palagonite” or doleritic districts do we
find some lakes and rivulets. Rivulets are very short: they very seldom
reach the sea but disappear suddenly in lava fields. During heavy
rains, subterranean channels sometimes are not able to lead all the
water to the sea; subsequently, small periodical pools may be seen in
such places, e. g. in Lækjarvellir at Djúpavatn.
L a k e s of different types may be seen on the Reykjanes Peninsula.
Most of them are of glacial origin and are in most cases very shallow
or even periodical. Also volcanic lakes — “maar’s” are numerous in
the area investigated. They are very deep, as e. g. Grænavatn in Klei-
fardalur. Lakes of the coastal type or of other types are rare. The
greatest lake is Kleifarvatn.
The climate of Reykjanes is fairly known in the coastal district,
but the interior of the Peninsula is climatically unknown. Average
temperature from Eyrarbakki (21 years) and Hafnarfjörður (22 years)
from the period of 1874—1901 (cf. Thoroddsen, Botany of Iceland
1. 1. 1914) may be seen in the following table:
I II III IV V VI VII VIII IX X XI XII year:
Eyrarbakki: —2.1 —i.j —1.6 2.4 6.1 9.3 11.0 10.3 7.5 3.0 0.2 —2.1 3.6° C
Hafnarfjörður: —i.j —0.9 —0.9 2.7 6.1 9.3 11.0 10.5 7.6 3.J 0.7 —i.j 3.90 C
The climate of the interior of Reykjanes may be analogical of the
climate of Gilsbakki in the inner part of West Iceland (cf. Thorodd-
sen 1. c.):
I II III IV V VI VII VIII IX X XI XII year:
Gilsbakki: —3.9 —3.7 —3.8 —0.4 4.0 7.9 9.4 8.6 6.1 1.6 —1.4 —3.5 +i.7°C
Precipitations are great in SW Iceland; the greatest are in Vest-
mannaeyar: 1319.6 mm per year, maximum 62.6 mm a day (cf.
Thoroddsen 1. c.).
I should think that the warmest part of the district is the south-
eastern part at Herdisarvík. Precipitation is greatest in the Central
Highland and in Krísuvíkurdalur. /
The Soil.
Soils of the Reykjanes Peninsula are for the greatest part allochtho-
nous which is not surprising in a country with such strong erosive
factors as Iceland. The most common type of soil is the Icelandic