214 KJELLMAN, THE ALG OF THE ARCTIC SEA. 
mens of A. esculenta by the stipe thickening upwards towards the rhachis, by the upper 
part of the stipe being somewhat flattened as well as the rhachis and broadly elliptical 
in transverse section, by broader and longer sporophylls which are distinctly stalked and 
the basal parts of which are somewhat thickened downwards and united by a thin margin, 
by the distinctly wavy ovate-lanceolate lamina whose base especially in older individuals 
is far more rounded, sometimes almost heart-shaped and always less decurrent than in 
A, esculenta, and by the costa being lower and less sharply marked against the lamina 
than in A. esculenta. In drying the plant becomes more dark-coloured than the last- 
mentioned alga. I consider the species in question identical with A. Pylaii J.G. Ac. The 
specimens agree in all essential points with J. G. AGArpn’s description, and on comparing 
them with Greenland specimens of A. Pylaiw no constant essential differences can be 
detected. However, the Norwegian specimens are often narrower than those from Green- 
land and provided with narrower sporophylls. But on the other side there exists 
on the coast of Norway a litoral form of the plant, which resembles the specimens from 
Greenland with regard to the breadth of the lamina as compared with the length and 
surpasses them in the breadth of the sporophylls. It should be remarked also that even 
among the specimens from Greenland distributed by J. G. AGarpu under the name of 
A. Pylau there are to be found several that have a more elongated lamina and nar- 
rower sporophylls. Between these and the sublitoral form from the north-west coast of 
Norway I have not been able to detect any differences. In all the young individuals 
from the Norwegian coast that I have seen, the stipe is very short, 5 cm. in length at 
the most. In some of them that part of the frond which is below the sporophylls is 
even 20 cm. long, but this is plainly no stipe proper, but the stipe together with the 
rhachis which elongates as the plant grows older, developing new sporophylls above 
the old ones which fall off after having served their purpose. In one of these older 
specimens whose axial portion below the collection of sporophylls is 15 cm. long, there 
is to be seen on either side of the axis a ridge which becomes more and more indi- 
stinct downwards, but can be traced with certainty to a distance of 5 cm, from the rhi- 
zines. These ridges obviously mark the part that has once borne sporophylls. All 
that part of the cauloid portion which is provided with those two ridges is accordingly 
to be regarded strictly as belonging to the rhachis, not to the stipe, so that the stipe 
itself is really short even in those old individuals in which the cauloid portion is long. 
The rhachis is long, on the contrary, longer than in A. esculenta and even longer than 
in f. muse@folia, in which I have never found any muricate margin, but only a short 
row of cicatrices of fallen sporophylls, depressed in a furrow. 
I think Guyner’s Fucus pinnatus should be referred to the present species rather 
than to A. esculenta f. musefolia. If the proportions between the length and the breadth 
of the lamina are at least approximately correct in the figure quoted, I cannot see how 
such an Alaria could possibly be referred A. museefolia. Also with regard to the shape 
_of the lamina the plant figured agrees more nearly with A. Pylaii than with any A. 
esculenta that I have seen. To+these facts is to be added the form of the rhachis which 
seems to me to point very decidedly towards the identifying of Fucus pinnatus with A. 
Pylaii, not with A. esculenta f. musefolia. Supposing the figure to be delineated from 
