The Botany of Iceland - 01.12.1912, Side 180

VIII. SOME NOTES ON THE BIOLOGY OF THE
ALGÆ ALONG THE COAST OF ICELAND.
t present very little is known with regard to the biology of
the marine algæ along the coast of Iceland. What is known,
on the whole, regarding this point is for the most part mentioned
in the “Marine Algæ of Iceland” (31) under each species. Some ob-
servations which have been made subsequently will be mentioned
in the following pages. Of these, I regard tliose which have been
made during winter as the niost important, altliough they are very
incomplete owing to the fact that during winter I have only rarelv
been able to make investigations, and then have liad access to the
littoral zone only; thus, with the exception of a few species, the
winter-habit of the sublittoral species is not known. Consequently
I can, by no means, treat of the biological conditions exhaustively,
but must content myself with giving a few incomplete contributions.
On the wliole, the behaviour of the species is best known in
spring and summer, less well in autumn, and least well during
winter. From most of tlie coastal districts there are observations
to hand either only those of a single season of the year, or at most
of two or three seasons. From Reykjavík we have observations of
all four seasons, but those of the winter are sparse, and only a few
species have been observed throughout the year.
The observations to hand are so few and insufficient that a
comparison of the biological conditions in the five coastal districts
in question cannot be made; here, therefore, Iceland is treated for
the most part as an entirety.
1. Duration of Life.
The life-period of the algal species is of very varying length ;
in this connection the algæ mav be divided into two groups: annual
algæ and perennial algæ.