KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 20. N:0 5. 213 
have come from more northern localities, are distinctly marked with the characteristics 
set down by J. G. Acarpu for A. muswfolia. Some of them might very well have 
served as original for De La Pyvate’s figure of Laminaria esculenta var. platyphylla, 
which is regarded by J. G. AGarpu as the typical A. muswfolia. Between these two 
plants, A. esculenta and A. muse@folia as understood in this sense, no fixed limits can 
be drawn. The one, A. musefolia, is a northern fori, the other, A. esculenta, a southern 
form of the same species, I have been able to lay out a complete series of transitions 
between them. 
In order to show what the dimensions of this beautiful species are in our seas, | 
shall give the measures of the largest specimens at my disposal. The stipe is 15 cm. 
long, one cm. in diameter downwards; the rhachis has a length of 5 cm., the naked costa 
above the rhachis a length of 2 cm.; the lamina is one metre and a half long and 12 cm. 
broad at its broadest part, which is situate 35 cm. above the base of the lamina. The 
leaves are 12 cm. mm length and 1 cm. in breadth. That Mucus pinnatus Gunn. belongs 
to this species, seems to me very dubious. I believe it is to be identified with Alaria 
Pylai J. G. Ac. I shall return to this question in my account of the last-mentioned 
species. 
Habitat. The present species lives gregarious at low-water mark or somewhat below 
that line in the uppermost part of the sublitoral zone, principally on solid rocks in 
exposed localities. It is found still flourishing at the end of August, but its highest 
development seems to be attained during the earlier part of the summer. On the arctic 
coast of Norway I have found individuals with mature zoosporangia in July. 
Geogr. Distrib. Undoubtedly it reaches its maximum of frequency in the southern 
part of the Norwegian Polar Sea; at Finmarken it is scarce, being replaced here by 
A. membranacea. It is also reported from the Greenland Sea by J. G. Acarpu, but I 
have failed to detect it here myself. 
Localities: The Norwegian Polar Sea: Nordlanden common; Finmarken: Maasé 
local and scarce. 
The Greenland Sea: the coast of Spitzbergen according to AGaArpu. 
Alaria Pylaii (De ta Pvt.) J. G. Ag. 
Grénl. Lam. och Fue. p. 24. Laminaria Pylaii De La Pyx. Fl. Terre neuve p. 29. 
Deser. Alaria Pylaii J. G. Ag. 1. ¢. 
Syn. Alaria Despreauxii J. G. Ac. Groénl. Alg. p. 110. 
» esculenta KLEEN, Nordl. Alg. p. 32; ex parte, fide syn. 
» Pylaii CroauL, Fl. Dise. p. 457. 
Fucus pinnatus Gunn. Fl. Norv. 1, p. 96(?). Acta Nidros. t. 8, fig. 1(?). 
Remark on the species. Besides Alaria esculenta as I have understood above, there is 
to be found on the north and west coasts of Norway at least northward from Aalesund 
another Alaria which is certainly specifically distinct from the former. [| possess a con- 
siderable number of specimens of it, both young ones bearing their first sporophylla 
and older ones with scars of fallen leaves. They are easily distinguished from speci- 
