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my specimens; plants with foursided midrib are met with only now and 

 then. The transverse section of the lower part of the midrib sometimes 

 has a six-sided shape (fig. 22, e) and occasionally I have met with plants 

 having an unilaterally developed midrib (fig. 22, f). 



The length of the lamina is varying from 60 — 500 cm. and the 

 breadth from 8 — 30 cm. The base of the lamina is wedge-shaped or 

 sometimes rounded, in specimens with narrower lamina it is more or 

 less decurrent. The upper part of the lamina is usually split down to 

 the midrib and the uppermost part of it consists most frequently only 

 of the costa. I have never met with specimens in change of lamina, 

 but I have occasionally (e. g. at Reykjavik and Dyrhölaey) in the spring 

 and summer met with plants having long and thick, evidently several 

 years old stipes and long, narrow and thin, evidently young laminæ. 



The sporophylls are 10 — 36 cm. long and 1 ,5 — 5 cm. broad, usually 

 narrowly wedge-shaped at the base and broadest at the top, sometimes 

 the upper and the lower part are almost equally broad. Sometimes the 

 sporophylls, especially when narrow, are placed very densely, in other 

 cases they are far distant. 



Some of my specimens come near to f. australis Kjellm. (Handbok 

 I.e.), namely, specimens having narrow lamina and decurrent base, they 

 differ from it mainly by greater size and longer stipe. That difference, I 

 think, is of no essential import, as the size of the plant and the length 

 of stipe are varying according to age. On the south-coast of Iceland I 

 have met with specimens cast ashore, fully agreeing with Strömfelts de- 

 scription (1. c.) and original specimens of f. fasciculata (Fig. Fl. Dan. tab. 

 417). The greatest part of my material, I think, is referable to î.pinnata 

 (Gunn.) Kjellm. (Handbok 1. c), but the Icelandic specimens attain a much 

 greater size. I have met with plants, which had a total length of 7 m. 

 and a 30 cm. broad lamina. 



Alaria linearis Strömf. (1. c.) is, according to the description and 

 original specimens, to be regarded, if not fully identic to f. australis Kjellm. 

 as most closely related to it. 



Alaria flagellaris Strömf. (1. c.) is established on young, undeveloped 

 plants, which in all respects resemble young specimens of A. esculenta, 

 which I have met with, and described above. A. flagellaris Rosen v. 

 (1. c.) is identic with fully developed specimens of f. pinnata, as here 

 understood. 



Specimens of Al. esculenta with narrow lamina are only by the shape 

 of the costa distinguishable from specimens of A. Pylaii f. membranacea 

 with narrow sporophylls. 



This species is exceedingly common along the coasts of Iceland, and 

 occurs gregariously in the sublitoral region down to a depth of 15 fathoms. 



