The Botany of Iceland - 01.12.1912, Blaðsíða 71

MARINE ALGAL VEGETATION
57
Witli respect to the 6 species (A, 9—14) which have been found
only in N. Iceland, it cannot be assumed that they are confined to
the north coast, and it is highly probable that they have a much
wider distribution on both sides. Dictyosiphon corijmbosus and Ulo-
thrix consociata v. islandica must, however, be assumed to belong
more closely to E. and N. Iceland.
As regards the 8 species (A, 15—22) which occur so far west
or south as NW. Iceland or SW. Iceland, it must be supposed that
their absence from N. Iceland (and E. Iceland [Ceratocolax, CruoriaJ)
is due merely to insufficient knowledge regarding their distribution.
Of these species, those which extend to SW. Iceland have not been
found, however, further south than in Breiðifjörður, with the ex-
ception of Peyssonetlia which has been found in Faxaflói near
Reykjavík.
Of the species given under A, Nos. 1—8, 12 and 14—23 must
consequently be supposed to have an east-northward distribution
along the coast of Iceland, while Nos. 9, 11 and 13 must be sup-
posed to have some other principal distribution; one species (10) is
endemic in the most western part of the north coast.
Under B, 53 species are recorded. Of these 10 have been found
only in S. Iceland, the majority of these in the Vestmannaeyjar
only; to these must be added Bonnemaisonia (31, p. 141) which I
believe to Iiave been found in S. Iceland. That is, 11 species in all,
one of which, however, Rhodochorton repens, is endemic. 17 species
have been found only in S. and SW. Iceland (B, 12—28) and 8 species
in SW. Iceland only. Thus, there are in all 36 species which are
known from S. and SW. Iceland only. 6 species (B, 37—42) have a
more northern distribution, as they have been found in NW. Ice-
land. Consequently, there are 42 species which are known only
from S. and W. Iceland (NW. Iceland included), but of these species
there are two, Cladophora rupestris and Codiolum Petrocelidis which
probably have a more northern distribution. 10 species (B, 43—52)
which have principally a south-western distribution (the fact that
some of them liave not been found in NW., SW. and S. Iceland is
probably due to insufficient knowledge regarding their distribution)
have been found also in N. Iceland. But all these species do not
reach eastward along the north coast to the same extent, Ptilota
plumosa and Corallina officinalis have been found furthest east in
the eastern part of the north coast; Lithophyllum Crouani and
Myrionema vulgare in Eyjafjörður; Ahnfeltia and Petrocelis extend to