Flora and Vegetation of Iceland: Encyclopedia Arctica 6: Plant Sciences (Regional)
Flora and Vegetation of Iceland
(EA-Plant Sciences. Askell Löve)
FLORA AND VEGETATION OF ICELAND
| Page | |
| Topography | 1 |
| Climate | 3 |
| Flora | 4 |
| Vegetation | 6 |
| Moist Soils | 6 |
| Dry Soils | 14 |
| Bibliography | 23 |
EA-PS. Love: Flora and Vegetation
in of Iceland
| Page | ||
| Fig. 1. | The main nunatak areas during the maximum glaciations | 3a |
EA-PS. Love: Flora and Vegetation of Iceland
graphs for possible use as illustrations. Because of the high cost of
reproducing them as halftones in the printed volume, only a small propor–
tion of the photographs submitted by contributors to Encyclopedia Arctica
can be used, at most one or two with each paper; in some cases none. The
number and selection must be determined later by the publisher and editors
of Encyclopedia Arctica . Meantime all photographs are being held at The
Stefansson Library.
EA-Plant Sciences
(Askell Love)
between Scotland and Greenland, has a surface of about 104,785 square kilo–
meters. Its southernmost point lies at 63°19′ N. latitude, its northernmost
isle at 67°07′ N. latitude, its westernmost point at 24°32′ W. longitude, and
its easternmost skerry at 13°16′ W. longitude, the Arctic Circle touches the
northeastern part of the mainland. The shortest distance from Iceland to
Greenland is about 300 kilometers, to the Faeroes it is about 420 kilometers,
to Scotland about 800 kilometers, and to the Norwegian coast about 970 kilo–
meters.
cene, and Holocene, subsequently molded by abrasion, faults, and other denuding
agencies. The principal rocks are basalt and palagonite breccia, attaining a
total thickness of perhaps 4,000 meters. The oldest layers are at least some
200 meters below the present sea level, but the rocks underlying the basalt
formation are as yet unknown. In Paleocene times about half the total thick–
ness of the basalt was formed, and in the Eocene a lignite formation up to 50
meters thick accumulated, indicating a long period without great change. The
plant remains of this formation seem to suggest a climate of perhaps similar
character to that at present found in the temperate areas of North America
EA-PS. Lõve: Flora and Vegetation of Iceland
and southern England, although the remains have, so far, not been thoroughlystudied from modern viewpoints. It is suggested that during the Eocene the
mean annual temperature of the island was about 7° to 10°C higher than at
present.
preglacial times a broad central zone of submergence, now filled up by the
palagonite , was formed. It is in this district that almost all the present–
day volcanoes are found. In the west and east, large areas are formed entirely
by the old basalt layers.
topographical levels above the submarine shelf are discerned: ( 1 ) the coastal
and the valley plains from sea level up to an altitude of about 100 meters,
and (2) the tableland from about 600 up to about 1,000 meters. In the central
part of the country, however, at least three such levels are found: ( 1 ) the
coastal plains up to about 100 meters, ( 2 ) the Inland plateau or tableland
from 300 to 600 meters, and ( 3 ) the plateau horsts from 1,000 to 1,800 meters.
Above the plateau horsts some isolated volcanoes reach up to 2,118 meters (in
the case of Oraefa jökull). The present glaciation is mainly connected to tea
plateau horsts and volcanoes, as its limit is generally above 1,000 meters.
much indented except in the south, but practically no coastal archipelago is
found. Although lowlands are fairly plentiful in the west, southwest, and
south, they are estimated to occupy not more than one-fifteenth of the country
as a whole.
nent ice, but during the Pleistocene glaciations only snail areas were
EA-PS. Lõve: Flora and Vegetation of Iceland
unglaciated; exceptions were in the mountainous coastal regions in the north–west, east, and between Skagsf jördur and Skjalfandi in the north — i.e., the
so-called Eyjaf jördur district, the history of the glaciations in Iceland has
not been very closely studied as yet, but according to some geologists rather
large nunatak areas did exist within the above-mentioned areas during the max–
imum glaciation; it is to be presumed that on them persisted both plants and
small animals (see Fig 1.)
plant species occurs They are mainly restricted to the basalt regions.
was disrupted in the late Miocene, and since then the country has been an iso–
lated island. This is, however, mainly an assumption.
warm Gulf Stream mingle. The climate seems best considered subarctic in most
parts of the island. The mean temperature of July, the warmest month, varies
from approximately 7.2° to 10.6°C. (45° to 51°F.), but the winter temperatures
are not very low, the lowest January mean on record being −6.1°C. (21°F.), and
the highest l.4°C. (34.5°F.). The mean temperature during the year varies
from about 0° to 5°C, (32° to 41°F,). Frost may, however, be experienced in
every month of the year in all localities. In all places the weather is very
stormy, and the precip it ation is considerable in the southern and western parts
of the country, The snow lies in the northern lowlands for as much as 3 1/2
months in an average year, but only for 1 to 1 1/2 months in the southern parts
of the country. Solifluction is more common in the southern than in the northern Fig. 1. The main nunatak areas during the maximum glaciation.
EA-PS. Lõve: Flora and Vegetation of Iceland
lowlands, but permafrost exists only in the inland plateau, mainly in thenorthern and eastern parts of the country, where precipitation during the
w inter months is relatively small. In some years the arctic drift ice will
affect the spring and summer temperatures, at least in the northern parts
of the country, but in most years it will only be found for a short time off
the north coast. Nevertheless, only in one year out of every five has the
coast been completely free from drift ice daring the last 150 years.
have never been studied by a trained botanist, and only a few collections of
lower plants have been made by specialists. The number of species known is,
therefore, by no means complete, and some of the species and their lower units
are not as yet fully determined. The total number of species known at present
seems to be about 3,600, bacteria excluded. Of these, about 770 are freshwater
or marine diatoms; about 300 are other freshwater and aerial algae; the marine
algae recorded are only 200 (exclusive of diatoms); about 1,000 species of
fungi are known from the island; the lic
bryophytes collected are about 450; 33 species of pteridophytes are known;
and about 550 spermatophytes, including Taraxacum and Hieracium . Of these
figures, however, only those of the spermatophytes, pteridophytes, and marine
algae are based on really detailed studies in many parts of the island.
Pleistocene glaciations in the nunatak areas of the coastal refuges. This
suggestion is not only based on geobotanical studies of the present flora, but
also supported by studies of the flora of the interglacial layers observed in
EA-PS. Lõve: Flora and Vegetation of Iceland
some places in the southwest and north. According to preliminary calcula–tions, at least 55% of the present flora of higher plants belong to the group
of glacial survivors; about 30% may have been introduced by man during the
last 1,000 to [ ] 1,200 years; but the remaining 15% might perhaps belong to
the first-named group or have dispersed from other regions in postglacial
though prehistoric times. Among the lower plants, the percentage of glacial
survivors is estimated to be still higher.
Those known at present among the higher plants are:
var. islandicum , Sesleria varia subsp. Islandicum , Roegneria ( Agropyron )
doniana var. stefanssonii , R. borealis var. islandica , Dactylorchis maculate
subsp. islandica , Silene maritima subsp. islandica , Papaver radicatum subsp.
islandicum and subsp. stefanssonii , Euphrasia rotundifolia , E. davidssonii ,
Galium pumilum subsp. islandicum , and several Hieracium and Taraxacum micro-
species. If we exclude the last-named apomictic groups, less than 2% of the
flora of higher plants are so far known to be endemic types. However, this figure
will certainly become higher when closer studies of all the species are per–
formed.
group of circumpolar or at least circumboreal species, a rather high percentage
belong to groups present in Scandinavia or Eurasia but not in northeastern
America. There are also some species which belong to the group of “west-arctic”
plants, occurring in eastern North America, Greenland, and northern Scandinavia,
but not in Asia; and some species of this group are not met with in Scandinavia,
their area of distribution reaching from North America to Greenland and Iceland
only. The most remarkable of these plants of more restricted range are:
EA-PS. Lõve: Flora and Vegetation of Iceland
Elymus mollis ( E. arenariuPlatanthera ( Habenaria ) hyperborea , Salix cordifolia var. callicarpea , Cakile
edentula subsp. typica , Saxifraga aizoon subsp. neogaea , Epilobium latifolium ,
Galium brandegeei , and Plantago juncoides var. glauca . Of the mosses, at
least Bryoxiphium norvegicum belongs to this group.
of species withstanding the wet and relatively cold climate. Typical alpine
species are met with at sea level in the southwestern portions of the country
as well as about the outer parts of the fjords in the other regions, but in
the inner parts of the fjords in northern Iceland and the inner lowland in
the east, the climate is more continental and real alpine species are not found
at the lowest altitudes. The tree limit is at 200 to 300 meters in southern
and western Iceland, but in the northern and eastern parts it may reach up to
500 or 600 meters.
shelf is not very complicated and its characteristic types are almost the
same as in northern Norway and southern Greenland. Farthest from the coast
only the formation of crustaceous algae is met with, followed toward land
by the Lithothamnion, the deep-water associations of the Floridion (mainly
Polysiphonetum arcticae), the Desmarestion, and different associations of
the Laminarion, the Laminarietum digitatae, and the Laminarietum hyperboreae.
These are the communities of the depths, the Laminarietum saccharinae form–
ing most of the vegetation nearest the coast. Above this sublittoral zone
EA-PS. Lõve: Flora and Vegetation of Iceland
the Corallinion is met with, followed by Polysiphonetum urceolatae, Rhodomenion,Chondetum, and Monostrometum. The comes the real littoral zone, dominated by
the Fucion and some communities of filifrom algae, the Ulotrixetum, Codioletum,
Bangietum, and Porphyretum. In the inner fjords of the west coast the Zoster–
etum occupies relatively large areas of muddy clay in the sublittoral zone, al–
though it became very much decimated by disease during the period 1930 to 1940
as in other parts of the North Atlantic. At one place only, in somewhat brack–
ish water in the sublittoral zone, the Ruppietum maritimae was observed.
munities are met with on stones and rocks, but on sandy and gravelly coasts
where the winter storms drive in masses of wracks ( Fucus app.) the outposts of
higher vegetation are hapaxanthic species of Polygonum , Atriplex , and various
Cruciferae. On the sandy and gravelly beaches above this zone, there occurs
more or less open vegetation characterized by Cakile edentula , Arenaria peploides ,
Potentilla anserina (in the northernmost parts P. egedii ), Mertensia maritima ,
and Tripleurospermum maritimum . This zone seems to merge into the next which
consists of Festucetum cryophilae, Puccinellietum, and Agrostidetum, intermixed
with Polygonum heterophyllum , Silene maritima , Cochlearia , Potentilla anserina ,
Thymus arcticus , Plantago maritima (in the northernmost parts P. juncoides var.
glauca) , Galium verum , and other more or less typical coastal plants.
marsh is apt to be formed in places flooded by the sea during some time of the
year. The vegetation of these marshes seems to be exclusively the Puccinellie–
tum maritimae mixed with a few individuals belonging to the general Carex ,
Juncus , Scirpus , Triglochin , Potentilla , and Plantago .
EA-PS. Love: Flora and Vegetation of Iceland
of steep cliffs, often populated by sea birds during the spring. Such situa–
tions are very rich in vegetation, the most frequent communities being com–
posed chiefly of Festuca , Poa, Cochlearis , Sedum rosea , Angelica archangelica ,
and Ligusticum scoticum . On the cliffs thems
and mosses from their varied and often colorful communities. On the more
grassy parts of the cliffs, Potentilleto-Bistortion vivipari and communities
belonging to the Ranunculeto-Oxyrion or the Geranietum silvatici are often
mixed with the Festuceto-Poeticum.
eutrophic and oliotrophic water, but the difference has not yet been very
closely studied in Iceland. In deep lakes only Characeae and other algae
are met with, but in shallow lakes the vegetation belongs to the Littorellion,
including species of Isöetes , Littorella , Subularia , Callitriche , Myriophyllum,
Hippuris , and some other plants. The associations belonging to the Potamion
euro-sibiricum are common at least in the eutrophic lakes. Its typical repre–
sentatives are various species of P
the Equisetetum fluviatile and Caricetum rostratae-Lyngbyae, follow
d r ier margins by Caricetum fuscae (with the moss Drepanocladus exannulatus )
and other marsh communities.
the lakes when the current is slow; but in rivers and streamlets with a strong
current, there are rather few higher plants — except, of course, at the banks.
Nostoc spp. And other algae together with such mosses as Fontinalis , Hygrohyphnum
EA-PS. Lõve: Flora and Vegetation of Iceland
and Rhynchostegium are frequent in the rivers, but in glacier streams no mossesor higher plants are to be found.
in both the lowland and the highland is extremely rich in mosses. Most of the
vegetation of the springs seems to belong to alpine associations. Examples
are ( 1 ) Mniobryo-Archangeletum and ( 2 ) Mniobryo-Epilobietum hornemanni, which
are not restricted only to the highlands, ( 3 ) Philonoto-Saxifragetum stellaris,
which is common almost all over the country, and ( 4 ) some communities belonging
to the Cratoneureto-Saxifragion aizoides in the northern and eastern parts of
the country. These last include the Cratoneureto-Crepidetum paludosae, the
Cratoneureto-Saxifragetum aizoides, and some other communities occupying small areas and involving
Cratoneuron glaucum , Bryum ventricosum , Equisetum variegatum , Epilobium alsini–
folium , and some other species.
algae and mosses, but as a whole it seems to be composed mainly of different
types of the Icelandic marsh and spring communities. About thirty species of
mosses, some higher plants, and several species of algae are exclusively met
with [ ] on warm soils. Drawf forms of higher plants are typical for such locali–
ties, owing to the effect of the high temperature on the time of flowering;
but these forms are only modifications.
may most easily be subdivided into two groups, the eutropic-mesotrophic marshes
or Caricetalia fuscae, and the meso-oligotrophic marshes or Scheuchzerietalia.
In addition, there are the shrub marshes or Oxycocco-Ledetalia, which are met
with in some areas.
i.e., they are formed mainly in places with running groundwater or those that
EA-PS. Löve: Flora and Vegetation of Iceland
are influenced by water from rivers and streamlets. They are grouped intotwo rather different types of marshes, the Caricion atrofuscae-saxatilis,
which is mainly found on basic soils in the lowlands, and the Caricion canescentis-fuscae,
which is met with on more or less neutral soils and at high as well as low
levels.
saxatilis association
Caricetum microglochinis marshes are met with. Their characteristic species
seem to be Carex microglochin , C. maritime , C. capillaries , C. fusca , Juncus
triglumis , and perhaps Bistorta vivipara ( Polygonum viviparum ), Epilobium
latifolium , and Pinguicula vulgaris ; the mosses most frequently associated
[ ] are Climacium dendroides , Drepanocladus intermedius , Philonotis tomen–
tella , Oncophorus virens , and Swartzia Montana . Some lichens such as Cetraria
nivalis are frequently met with, and various species of higher plants charac–
teristic of dry and moist soils may be associated in these marshes.
are sometimes observed. They are rich in species and a useful indicator of
excellent soils. One of the two most characteristic species from Europe,
Carex atrofusca , is not found in Iceland, but this marsh type in Iceland is
characterized by C. vaginata , with C. dioeca , C. norvegica , C. saxatilis ,
C. adelostoma (in a few places in the northwest), Salix cordifolia var.
callicarpea , Betula nana , Bistorta vivipara , Thalictrum alpinum , Vaccinium
uliginosum , and several other species which are always found in these marshes.
Their cryptogamous flora is also rich in species, although only Blindia acuta ,
Drepanocladus exannulatus , D. intermedius , and the lichen Cetraria islandica
are always present.
EA-PS. Löve: Flora
[
]
a
nd Vegetation of Iceland
cetum saxatilis fens predominate, with the characteristic Carex saxatilis
mixed with some individuals of Eriphorum angustifolium . In the drier parts
of this association, individuals of Equisetum arvense, Juncus triglumis , Salix
cordifolia var. callicarpea , Bistorta vivipara , and various other species of
higher plants are met with. The mosses always to be found in this association
are Bryum ventricosum , Campyli u m sp., and Drepanocladus intermedius .
Iceland and perhaps totally absent in its southern parts. In only two places
in northern Iceland has Carex flava itself been observed, but in other places
the characteristic species of the association appear to be Carex dioeca ,
C. capillaries , and C. fusca , Eriophorum angustifolium , Scirpus caespitosus
subsp. austriacus , Juncus filiformis , Nardus stricta , Leontodon autumnalis ,
Pinguicula vulgaris , Thalictrum alpinum , and the mosses Drepanocladus inter–
medius and Campylium sp.
caespitosi-trichophorum subarcticum, with Scirpus caespitosus subsp.
cus
Drepanocladus intermedius and Sphagnum spp. as well as a number of additional
species.
most common in Iceland, the main types being characterized as follows.
most common one being characterized by Carex fusca and C. canescens , with some
individuals of Eriophorum scheuchzeri , Juncus filiformis , Bistorta vivipara,
EA-PS. Löve: Flora and Vegetation of Iceland
Viola palustris , Pinguicula vulgaris , and the bryophytes Blasia pusilla , Bryumduvalii , Drepanocladus exannulatus , Oncophorus wahlenbergii , Pellia neesiana ,
and Philonotis fontana . In all marshes of this type, iron bacteria are common.
is met with especially in the zone between the above-mentioned moist one and
dry grasslands or heaths. It typical species are Carex fusca , Salix phylici–
folia , S. cordifolia var. callicarpea , Betula nana , Eriphorum angustifolum ,
and perhaps also Parnassia palustris subsp. neogaea , Ranunculus acris , Bistorta
vivipara , Viola palustris , and Equisetum palustre . The moss layer is composed
mainly of Bryum duvalii , Climacia dendroides , Drepanocladus sp., and Poly–
trichum
what sandy localities, and is frequently met with on relatively sterile, wet
soils along roadsides or in artificial holes in old marshes. Its species
are always few in number, those mostly observed besides Eriophorum scheuchzerii
being E. angustifolium and some Carices, with, in addition, the moss Drepano–
cladus exannulatus .
rostratae-canescentis are always small. The characteristic species are Carex
rostrata , Eriphorum angustifolium , and the mosses Calliergon stramineum and
Drepanocladus exannulatus . In some places Carex canescens is one of the
dominating species, although it is frequently replaced by Carex lyngbyei . In
the somewhat drier parts of these fens, other Carices, Potentilla palustris ,
Salix cordifolia var. callicarpea , and Spagnum sp. are not infrequent.
wide areas at least in the lowland is closely related to the one last discussed. The
EA-PS. Love: Flora and Vegetation of Iceland
dominants are: Salix cordifolia var. callicarpea , S. phylicifolia , Betulanana , Carex canescens , C. rostrata , perhaps C. lyngbyei and C. fusca , Erio–
phorum angustifolium , Potentilla palustris , and different moss species —
especially Paludella squarrosa and Spagnum warnsdorfii .
formed in places with a permanently high groundwater level, varying somewhat
with the seasons and the precipitation curve, but no
fluenced by springs. They may be divided into two rather different groups,
characterized in one case by the Stygio-Caricion limosae with loose and rotten
soil and few mosses, and a very poor algal vegetation in the microflora, and
in the other by the Leuko-Scheuchzerion, which is an uncommon type of Icelandic
marsh.
name fl
fens may be divided into at least four different marsh types: ( 1 ) The Stygio-
Caricetum chordorrhizae with the characterizing species Carex chordorrhiza ,
C. limosa , Eriophorum angustifolium , Drepanocladus exannulatus , Sphagnum sp.,
and perhaps also some of Carex lyngbyei ; ( 2 ) Stygio-Caricetum limosae, which
is a fen with Carex limosa and C. rostrata as the dominants, together with
Drepanocladus exannulatus and some liverworts; ( 3 ) Stygio-Caricetum lyngbyei
is a fen with Carex lyngbyei , C. fusca , and perhaps C. rostrata , Eriophorum
angustifolium , and Equisetum fluviatile, as well as Drepanocladus exannulatus
and some other mosses; ( 4 ) Stygio-Eriophoretum angustifoliae is a fen with
many variants, but Eriophorum angustifolium and Drepanocladus exannulatus as
the dominants.
EA-PS. Löve: Flora and Vegetation of Iceland
with only in [ ] very small areas. The chief type, perhaps, is that composed
of Eriophorum angustifolium , Carex rostrata , Sphagnum lindbergii , and Drepano–
cladus exannulatus , intermixed with Oxycoccus microcarpus if it is not absent
from the region in question.
hermaphroditi and are dominated or characterized by Empetrum hermaphroditum ,
Betula nana , Sphagnum fuscu
and Cetraria species. The most common associations seem to be: (1) the
Vaccinium uliginosum , Sphagnum fuscu
sometimes mixed with a few Carices, Eriphorum angustifolium , and Oxycoccus
microcarpus ; and (2) the Cladinoso-Empetretum hermaphroditum which is drier;
with Sphagna almost absent. The characterizing species are Empetrum , Betula
nana , Vaccinium uliginosum , and various species of Cladonia ; lichens are fre–
quently dominant, especially in regions with much wind erosion.
ing to the completeness of the plant cover. In the first group are the grass–
lands, the heaths, and the cultivated areas; in the second group are the wind-
eroded gravelly flats and sands and the clayey soils (Iceland ic
Nardeto-Agrostion tenuis association with frequent tussocks due to frost action,
etc. The most common communities are: (1) Festucetum rubrae subalpinum with
Festuca rubra , Poa pratensis subsp. alpigena , Agrostis tenuis , Potentilla
EA-PS. Löve: Flora and Vegetation of Iceland
crantzii , Alchemilla sp., Ranunculus acris , Taraxacum spp. and many othervascular plants, as well as mosses belonging to the general Torula , Brachy–
thecium , etc. This is also the vegetation of most of the cultivated grass–
lands without foreign grass species. (2) Agrostetum tenuis subalpinum is
also met with both in the grasslands and in the cultivated areas. Its dom–
inating species are Agrostis tenuis , Deschampsia caespitosa and D. alpina ,
Phleum commutatum , Bistorta vivipara , Ranunculus acris , Trifolium repens ,
Leontodon autumnalis , Taraxacum spp. , Alchemilla sp., etc. (3) Agrosteto–
Nardetum strictae is observed in some few places. It is characterized by
a high frequency of Nardus stricta , Agrostis tenuis , Festuca ovina and/or
F. vivipara , Anthoxanthum odoratum , Bistorta vivipara , etc.
thoroughly investigated as yet. They seem, however, to be classifiable
in the Rhacomitrion, Loiseleurieto-Arctostaphylion, Phyllodoco-Myrtillion,
and Juncion trifidi. The representatives of the Rhacomitrion are
ent types of the Rhacomitrietum, dominated by Rhacomitrium hypnoides and
other mosses. These communities occupy all the recent lava fields, as well
as stony flats in some areas of the lowland and highland, and they cover
wider areas than any other Icelandic plant federation. In relatively young
lava fields they are mixed only with a few species of lichens on the bare
stones, but later on Cladonia and Cetraria species are found in the moss cover.
They are followed by some few individuals of Carex bigelowii , Lycopodium
selago , Equisetum pratense , Festuca sp., Salix cordifolia var. callicarpaea ,
S. herbacea , Bistorta vivipara , Armeria maritima , Silene acaulis , Cassiope
hypnoides , Calluna vulgaris , Empetrum hermaphroditum , as step by step the
Rhacomitrion is altered into different associations with Vaccinium uligino–
sum , Salices, and different grasses, together with various mosses and lichens.
EA-PS. Löve: Flora and Vegetation of Iceland
In the end the vegetation of the lava fields will become typically heathy.to be: ( 1 ) the Loiseleurieto-Vaccinietum uliginosi, with Loiseleuria , Vac–
cinium uliginosum , Empetrum hermaphroditum , several grasses, and a great
many mosses and lichens. ( 2 ) The Arctostaphyletum uva-ursi, with Arcto–
staphylos , Betula nana, Calluna vulgaris , Vaccinium uliginosum , Festuca vivi–
para, Anthoxanthum odoratum , Cladonia sp., etc. (3) Vaccinietum uliginosi ,
which forms some different types of heaths, mixed with Juncus trifidus ,
Festuca vivipara , etc., and a great many mosses and lichens. ( 4 ) Empetro–
Betuletum nanae also forms heaths with Festuca vivipara and a great number
of mosses and lichens, of t
wind erosion. In some regions Empetrum hermaphroditum is almost absent from
some of these communities, but this tends to be compensated by Cladonia and
Cetraria . Rather wide areas are covered by associations with Salix cordifolia
var.
tions belong, perhaps, to a group which might be classified as ( 5 ) Lichenose–
Salicetum cordifoliae. Some heaths should be grouped in ( 6 ) the Empetro–
Cladinosum, that might only be a variant of (7) the Betuleto-Empetro-Cladinosum.
which is mainly met with in moraine areas with a light snow cover. It is char–
acterized by Betula nana , some small individuals of B. tortuosa, Empetrum
hermaphroditum, Vaccinium uliginosum, Festuca vivipara or F. ovina, and Cladonia,
Cetraria, Polyt
thick snow cover during the winter months. As the distribution of Phyllodoce
is restricted owing to historical factors, the most characteristic species of
this federation are Vaccinium myrtillus , Betula nana , Deschampsia flexuosa ,
EA-PS. Löve: Flora and Vegetation of Iceland
Empetrum hermaphroditum , and, in some parts of the country, Calluna vulgarisor Phyllodoce coerulea . Some of the groupings belonging to this association
are restricted to the vicinity of shrubby Betula tortuosa and are extremely
rich in thermophilous species.
as in the highland. The most remarkable groupings seem to be ( 1 ) the Festuce–
tum viviparae, with F. vivipara , Carex bigelowii , Luzula spicata , Cerastium
alpinum , Bistorta vivipara , Silene acaulis , Viscaria ( Lychnis ) alpina , Saxi–
fraga caespitosa , and Cetraria nivalis . In some places the dominating cryp–
togam is Rhacomitrium hypnoides . (2) Juncetum trifidi is not very common in
the lowland. It is formed mainly by Juncus trifidus , Festuca vivipara ,
Luzula spicata , Carex bigelowii , Dryas octopetala , Salix herbacea , as well
as some mosses and lichens. Thymus arcticus and Saxifraga oppositifolia
frequently form part of this community even in the lowland.
flats formed by wind erosion is, in all parts of the country, primarily
characterized by the Festucetum cryophilae mixed with Festuca vivipara ,
Agrostis stolonifera , Calamagrostis neglecta , Silene maritima , Cardaminop–
sis ( Arabis ) petraea , Epilobium latifolium , and some few other species.
All of these species are met with at all altitudes, not being bound especially
to the seaside; the same is true of Elymus mollis , which is found especially
on moving sands, together with Silene maritima , Potentilla anserina , etc.
In more fixed sand, the Festucetum cryophilae is intermixed with the Elymetum,
and such species as Armeria maritima , Galium verum , Kobresia myosuroides ,
Salix lanata , Salix cordifolia var. callicarpea , and some others may be met
with in these communities more or less incidentally. The succession seems
EA-PS. Löve: Flora and Vegetation of Iceland
to proceed from Elymetum mollis through Festucetum cryophilae and Festucetum–Agrostidetum to the closed community of the Festuceto-Salicetum lanatae. The
vegetation of the sands and gravelly flats is also characterized by some few
communities of mosses and lichens.
Their vegetation is unusually rich in therophytes, and it is suggested that
they are the result of frost and fluctuations in water level, making it im–
possible for the plants to form a permanent vegetation cover. The vegetation
of the clayey flats may be divided into three different associations: ( 1 )
the Koenigio-Sedetum villosi, which belongs to the Koenigio-Microjunceon
arcticum and the Epilobietalia alsinifolii; ( 2 ) the Eleocharetum acicularis
islandicum, which belongs to the Littorellion of the Littoretalia; and ( 3 )
the Limoselletum borealis of the Nanocyperion flavescentis of the Isöetalia.
The first-mentioned grouping is a typical subarctic one, the second is com–
pletely European temperate, but the third seems to be a mixture of arctic
and temperate elements.
of almost the same type as the vegetation of the lowlands as regards the
fresh waters, grasslands, heaths, gravelly flats, and marshes, although
these last and grasslands are less frequent and lowland species are often
not encountered in the slope vegetation. One type of vegetation is, however,
almost restricted to the valleys and slopes, namely, the Icelandic “forests.”
These are made up mainly of Betula tortuosa with Salix shrubs as well as
Betula pubescens var. coriacea , B. callosa , Sorbus aucuparia , and Populus
tremula , the two last-mentioned species being rare. The mean height of the
forest trees reaches only 2 to 3 meters, but the highest trees
EA-PS. Löve: Flora and Vegetation of Iceland
10 or 12 meters. The groupings met with in the Icelandic forests seem to bemainly the following: Betuletum Myrtillo-Hylocomiosum, Betuletum Empetro–
Hylocomiosum, and Betuletum Geraniosum subalpinum. In places without Betula
forests this last-named is represented by a Salicetum Geraniosum alpicolum, or
by Geranietum silvatici alpicolum. Apart from the trees, these communities
seem to be characterized by the occurrence of Geranium sylvaticum , Acetosa ari–
folia , Milum effusum , Anthoxanthum odoratum , Alchemilla sp., Angelica arch–
angelica , Hieracum sp., and in some parts of the country by Epilobium angusti–
folium and Roegneria ( Agropyron ) canina . Besides these species, a great many
of the most thermophilous ones in the Icelandic flora are met with in these
communities, which are found only in sheltered localities in the valleys.
erosion is too strong and the solifluction becomes too effective, the vegeta–
tion becomes very scanty — except in localities sheltered by ridges and
drifted snow. In these snow patches, the vegetation belongs mainly to the
Nardeto-Caricion bigelowii, Cassiopeto-Salicion herbaceae, and Ranunculeto–
Oxyrion. The main groupings of the Nardeto-Caricion bigelowii in Iceland are:
( 1 ) the Nardetum chinophilum with
herbacea , Bistorta vivipara , etc., and various cryptogams; (2) Anthoxantho–
Deschampsietum flexuosae with Anthoxanthum [ ] odoratum , Deschampsia flexuosa ,
Carex bigelowii , C. lachenalii , Lycopodium alpinum , Salix herbacea , Acetosa
arifolia , Gnaphalium norvegicum , Dicranum , Pohlia , Cetraria, and Cladonia spp.;
and (3)
well as Deschampsia flexuosa , Salix herbacea , Bistorta vivipara , Sibbaldia
EA-PS
.
Löve: Flora and Vegetation of Iceland
baceae are: ( 1 ) the mainly alpine Cassiopetum hypnoides which is generally
composed of Cassiope , Salix herbacea , Gnaphalium supinum , Carex bigelowii ,
and different mosses and lichens. ( 2 ) On the slopes as well as in alpine
regions, the Salicetum herbaceae boreale is characterized by Salix herbacea ,
Carex bigelowii , C. rufina (in some places only), Sibbaldia procumbens ,
Gnaphalium supinum , and different mosses and lichens. Here also is (3) the
Luzuleto-Ranunculetum glacialis, which is characterized by Ranunculus glaci–
alis , Luzula arcuata s.l., Poa laxa subsp. flexuosa , Cardamine bellidifolia ,
and other plants often found in open alpine soils.
to be: ( 1 ) the Phippsietum algidae with Phippsia algida , Cerastium sp., Carex
lachenalii , etc., at the margins of some glaciers and on high-alpine slopes;
(2) Saxifrago-Ranunculetum pygmaeii with Ranunculus pygmaeus , R. acris , Oxyria
digyna , Cerastium alpinum , Saxifraga cernua , S. rivularis , Sibbaldia procumbens ,
Veronica alpina s.l., Gnaphalium supinum , as well as Salix herbacea , Carex
lachenalii , and various mosses and lichens; (3) Oxyretum triviale, which is
formed mainly by Oxyria digyna , Ranunculus glacialis , Salix herbacea , Veronica
alpina s.l., and Gnaphalium supinum; (4) Ranunculetum acris
Carex bigelowii , C. lachenalii , Poa alpina , Festuca cryophila , Ranunculus acris ,
Acetosa arifolia , Bistorta vivipara , Oxyria digyna ,
procumbens , Alchemilla sp., Gnaphalium supinum , Taraxacum spp., Salix herbacea ,
and various cryptogams; and (5) Alchemilletum vulgaris chionophilum, one of
the most typical communities of the snow patches on the slopes and in the shel–
tered areas, which is composed primarily by species of the Alchemilla vulgaris
EA-PS. Löve: Flora and Vegetation of Iceland
complex, Deschampsia flexuosa , Sibbaldia procumbens , Salix herbacea , as wellas Taraxacum spp. Ver
etc.
stony soils below them is rather variable at different places. In the shel–
tered localities below the rocks, the most common communities seem to be
the Veronico-Poeticum glaucae with Poa glauca , P. nemoralis , Festuca vivipara
and F. ovina , Roegneria ( Agrop
fragilis , Sedum annum , Geranium sylvaticum , and [ ] other species; and the Arc–
tostaphyletum uva-ursi with Arctostaphylos , Anthoxanthum odoratum , Potentilla
crantzii , and perhaps Juniperus and some other species, where the soil is
not too bare.
tation belonging to the Dryetum and other groupings of plants that are able
to thrive in soils with a high degree of solifluction activity and wide varia–
tions [ ] in moisture content. In the crevices of the rocks themselves,
many thermophilous species are met with as individuals or limited associations,
examples being the Thymus arcticus-Saxifraga oppositifolia association, Sedum
roseum , the Saxifraga cotyledon-sedum roseum association in eastern Iceland,
Cystopteris fragilis , and other communities of higher and lower plants. On
wet palagonite rocks, Bryoxiphium norvegicum and other moss and higher plant
communities are met with, and on many of the basalt rocks in the mountains a
number of thermophilous species are found.
posed of the communities of the gravel flats, the sands, and the heaths of
EA-PS. Löve: Flora and Vegetation of Iceland
the slopes and lowland, although the number of species is lower and almostall thermophilous representatives are absent. In sheltered localities, how–
ever, different types of marshes are met with. Moreover, in the highlands,
the typical vegetation of clayey flats is absent, while it is only in the
hi g hlands of northern Iceland that the typical vegetation of the permafrost
areas, the tundra marshes, is encountered.
areas with a multitude of lakelets surrounded by fens of the Stygio–
Eriophoretum angustifoliae. Among these lakelets are giant tussocks up to
two meters in height and up to fifteen meters in length. The bogs between the
Stygio-Eriophoretum angustifoliae are covered with Eriophorum angustifolium-
Calamagrostis neglecta associations. On the slopes and domes of the tussocks,
however, the vegetation is clearly of the hea t h type, belonging mostly to
associations of Salix cordifolia var. callicarpea , Empetrum hermaphroditum ,
Cassiope hypnoides , Ristorta vivipara , Salix herbacea , S. lanata , Calamagrostis
neglecta , and fiferent Carices, while on the very tops of the driest tussocks
are found only communities belonging to the Rhacomitrion .
EA-PS. Löve: Flora and Vegetation of Iceland
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