214 KJELLMAN, THE ALG^ OF THE ABCTIC 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. 1 consider the species in question identical with A. Pylaii J. G. Ag. The 

 specimens agree in all essential points with J. G. Agardh's description, and on comparing 

 them with Greenland specimens of A. Pylaii 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. Agardh under the name of 

 A. Pylaii 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. muscefolia, 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 Gunner's Fucus pinnatus should be referred to the present species rather 

 than to A. esculenta f. muscefolia. 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. muscefolia. 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. muscefolia. Supposing the figure to be delineated from 



