The Botany of Iceland - 01.12.1912, Page 195

MARINE ALGAL VEGETATION
181
culosus, Ascophijllum nodosnm and Fucns inflatus). The vegetation
was as luxuriant during winter as in the other seasons of the year
when, however, the epipliyte-vegetation of tlie Fucus-belt is excepted.
For further infonnation concerning tlie Fucaceœ see p. 173. Epi-
phytes, for instance such as Pijlaiella littoralis and Etachista fucicola,
which at tlie other seasons of the year are conunon everywhere in
the Fíicus-bclt, were not observed. On the other hand, Polijsiphonia
fastigiata occurred in abundanee on Ascophijllum. Of intermixed
species in the Fucus-belt Cladophora rupestris may specially be
mentioned; it occurred abundantly as well-developed specimens with
the uppermost apex of the slioots destroyed.
A Hildenbrandietum occurred everywhere in the littoral
zone, of similar appearance and extent as at the other seasons of
the year.
In rock-crevices at the level of the Fuciis-belt a well-developed
Rhodochortonetum Rothii w;as found. The Rhodochorton was
sterile and Pleurocapsa amethijstea was growing upon it. In such
crevices were noted in addition: — Pylaiella littoralis, sterile and
in very small quantity; Acrosiphonia sp., a few filaments; Clado-
phora rupestris, abundant; Pohjsiphonia urceolata, sterile and with-
out hairs and sparse, and Callithamnion sp.
The vegetation of the Poois was on tlie whole veiy poorly
deveioped. The upper pools, at the level of Peluetia and Fucus
spiralis, contained a few srnall individuals of Cladophora sericea f.,
a few filaments of Pijlaiella littoralis, a few small individuals ol'
Monostroma fuscum, and Diatoms in abundance. In sucli pools
Cladophora sericea forms a dense and luxuriant vegetation in spring
and summer. Fucus inftatus f. linearis grows also in these pools in
spring and summer, Imt was not found there.in winter. Il appears
as if tliis form is annual, at any rate in the npper pools. The
lower pools, ahnost at the level of the lower parl of the Fucus-
belt, contained only a poor vegetation. Monostroma fuscum, how-
ever, occurred fairly abundantly, but Halosaccion ramentaceum was
found more sparsely; on Halosaccion was growing Elachista fucicola
v. luhrica with unilocular sporangia and somewhat sparse assimila-
tory íilaments, and also Ceramium sp.
Relow the Fucus-belt, in the lower littoral zone (upper part
of the semilittoral belt) were l'ound at Elferseyjargrandi, Rhody-
menieta distributed in patches here and there, many of tliem of
rather considerable size. The majority of the individuals were old,