Flóra: tímarit um íslenzka grasafræði - 01.04.1966, Side 95

hyp7ioides) er allmikið, vex það einkum utan í þúfum. í 9 ber mest á
stinnustör (C. Bigelowii). Fremur snjóþungt er á öllum þessum
stöðum.
Síðan þetta var ritað, hefi ég séð flétturík heiðarlönd á allstórum svæðum á heið-
unum suður af Húnavatnssýslu, einkum þó á Auðkúluheiði. En þar sem þessi rit-
gerð er miðuð við tiltekin öræfasvæði en ekki allsherjarlýsing, er þeirra athugana
ekki getið hér, hins vegar mun flest það sem sagt er hér um fléttuheiðina eiga við
um þau svæði.
ON THE VEGETATION OF THE CENTRAL HIGHLAND
OF ICELAND.
PART THREE
By StemcLór Steindórsson, Akureyri College, Akureyri
The third part of this paper deals with the heath vegetation of the central high-
land of Iceland, which falls into three main formations.
A. The Graminé heath is characterized by grass and grasslike plants. Kobresia
wyosuroides dominates, but other common species are Juncus trifidus, Festuca
rubra and Carex Bigelowii. The formation is poor in shrubs often closely related
to the Rhacomitrium heath. Two sociations are described 55—56.
B. The Dwarf-shrub heath is divided into three formations: a) Empetretum
hermafroditi with dominating E. liermafroditum. Common species are Loiseleuria
procumbens, soc. 57, Vaccinium uliginosum, Carex Bigelowii, soc. 58, Betula nana,
s°c. 59, and Dryas octopetala, soc. 60. b) Callunetum vulgaris with two sociations,
Gl—62, occurs rarely at the altitude above 400 metres. c) Salicetum glaucae-lanatae.
In the sociations, 63—67. S. glauca predominates, but S. lanata in the sociations, 68
—71. The S. lanata sociations grow on dryer and more sandy soil than the others,
which may occur on such wet soil that it approaclies moor vegetation.
C. The Rhacomitrium heath. The Rhacomitrium dominates and always covers
more than 50% of the soil, and up to almost 100%. The formation falls into two
n>ain groups, Caricetum Bigeloiuii Rliacomitriosum, soc. 72—73, and Salicetum her-
baceae Rhacomitriosum, soc. 74—76. Rarely occurring types are Empetretum herma-
froditis Rhacomitriosum, soc. 77, and Equisetetum arvensis Rhacomitriosum, soc.
78. Closely related to the Rhacomitrium heath is Caricetum Bigelowii Lichenosum,
soc. 79, which perhaps were more correctly called Lichen heath. In connection
with the Rhacomitrium heath a formation is described which I have called mosa-
rnold (moss-mould). There the Rhacomitrium is almost lacking but more or less re-
placed by crusts of Anthelia and some other mosses. The phanerogams are very
scattered, and the soil is relatively bare and rather moist. This formation is possibly
an intermediate between the Rhacomitrium heath and the snowpatch vegetation.
TÍMARIT UM ÍSLF.NZKA GRASAFRÆÐI - FlÓm 93