The Botany of Iceland - 01.12.1912, Síða 177

MARINE ALGAL VEGETATION
163
Pterosiphonia parasitica. To show how rich in species the epiphytic
vegetation occurring on a single individual of L. hijperborea may
be, the following species, also from the Vestmannaeyjar, may serve:
Desmarestia viridis, Ptilota plnmosa, Delesseria sinnosa, Delesseria alata,
Lomentaria clavellosa, Polysiphonia urceolata, Plocamium coccineum,
Delesseria sanguinea and Euthora cristata.
So luxuriant and finely developed an epiphytic vegetation gives
to tlie Laminariaceœ-community of S. Iceland a character different
from that which it has in E. Iceland.
On the stipes of Alaria and Laminaria digitata, on the other
hand, a similar epiphytic vegetalion occurs in hoth the coastal
districts.
The zonal division of the marine algal vegetation is in its
main features siinilar in E. Iceland and S. Iceland, as is shown by
the following examples which have been taken straight from the
diaries.
East Iceland.
Vattarnes, steep cliiís,
highly exposed. l4/7.
I. Ulothricetum U. ilaccae.
II. Bangietum B. fuscopurpurae.
III. Porphyretum P. umbilicalis.
IV. Fucetum F. inflati, in the most
exposed localities, consisting
only of f. exposita.
V. Hhodymenietum.
Halosaccionetum.
Acrosiphonietum.
VI. Sublit. Alarietum.
Borgarnes, sloping rocky coast,
considerably exposed. 13/6.
I. Prasioletum P. stipitatae.
II. Ulothricetum U. flaccae, in great
abundance.
Rhizoclonium in crevices.
III. Bangietum B. fusco])urpureae,
in wonderful abundance.
IV. Porphyretum P. umbilicalis, of
great extent.
V. Monostroma groenlandicum.
VI. Fucus vesiculosus, sparse and
miserable.
VII. Fucetum F. inflati, abundantly.
The specimens very variable.
VIII. HalosaccionetumH.ramentacei.
Urospora Wormskioldii.
Polysiphonia urceolata.
Rhodomela lycopodioides.
Chorda tomentosa.
IX. Alarietum.
Hólmanes, somewhat exposed,
sloping rocky coast. 18/i.
I. Ulothricetum U. flaccae.
II. Enteromorphetum E. intesti-
nalis.
III. Fucetum, uppermost, narrow
margin of F. vesiculosus, be-
low that, broad belt of F. in-
flatus, intermixed here and
there sparsely with Ascophyl-
lum nodosum.
Under-veg. Hildenbrandietum.
IV. Halosaccionetum, intermingled
with Monostroma fuscum, Por-
phyra miniata, Rhodymenia
palmata and a few Fucus in-
llatus.
V. Alarietum, composed of Alaria
esculenta and A. Pylaii.
VI. Laminarietum L. saccharinae.
VII. Laminarietum L. digitatae.
11*