KONGL. SV. VET. AKaDEMIENS HANDLInGAR. BAND. 20. N:0 5. 113 



In summer the plant always presents an aspect of this kind. J. E. Areschoug 

 in Alg. Scand. Exsicc. Ser. 2. N:o 57 has distributed such specimens, collected in August. 

 Only exceptionally one finds some specimens of this kind during winter. 



The plant in winter habit. During winter and the earlier part of spring the plant 

 has the appearance shown by fig. 2 and produced by all the elements of ramification 

 being more or less completely dissolved. The elements 1 and 2 are most strongly re- 

 sorbed. Specimens of this kind are very common on the coast af Bohuslan in winter 

 during the months of December and January. 



The -plant in spnng habit. Fig. 3. Cp. Akesch. Alg. Scand. exsicc. Ser. 1. N:o 54. From 

 the portions that have persisted through the winter, branch-systems, sometimes scattered, 

 sometimes somewhat tufted, are developed, which produce sporocarpia and tetrasporangia. 

 These systems are decompound, with a corymbose development, and in this species attain 

 a more considerable size before the ripeness of the spores, than in the preceding one. 

 I do not know any antheridia in this species. I have taken specimens with ripe sporo- 

 carpia in May, with ripe tetraspores in April. 



The structure of the frond. The figures 4 and 5, both representing sections of the 

 lower part of the frond, show that outside the siphons there begins a mighty layer of 

 large-celled parenchyma, sharply defined without against a small-celled layer of tissue, 

 that is also mighty and passes without marked limit into the cortical layer. All cell- 

 walls are thick. The large-celled parenchyma is destitute of or poor in endochrome, 

 the small-celled is rich in endochrome. 



It is evident, that of these two species Rh. virgata has nothing to do with Rh. 

 lycopodioides. Rh. subfusca, on the contrary, presents so great a resemblance to certain 

 forms of this species, especially f. typica ft. laxa, that it may be questioned whether 

 they are indeed specifically distinct. Both have very often been confounded with each 

 other. All the specimens of the so-called Rh. subfusca, brought home by Kleen from 

 Nordlanden and come under my notice, are undoubtedly forms of Rh. lycopodioides; 

 and that plant from the coasts of Spitzbergen, which 1 have mentioned under the name 

 of Rh. subfusca, I must now allow to be a form of Rh. lycopodioides. Many instances 

 of that kind might be quoted. On that account, one might be inclined, like Gobi, 

 to unite these two Rhodornelee and to regard Rh. subfusca as a southern form of the 

 other. But, on the other hand, it is remarkable, that both the forms occur quite cha- 

 racteristical on the coasts of England, and that on the coast of Sweden Rhodomela 

 subfusca, in whatever localities it may grow, whether near the surface or in deep 

 water, is constantly alike in form, and, above all, never appears here in any densely 

 branched compacta- or densa-ioYin; whereas Rh. lycopodioides on the coast of Norway, 

 when growing between tide-marks, exhibits regularly the form typica compacta, but in 

 other cases assumes readily the aspect of f. typica ft laxa, which proves that these two 

 species or forms vary in a different manner. 1 must, moreover, call attention to a 

 difference between them, which, as far as my researches go, has shown itself to be 

 universal and constant. Rh. lycopodioides, in whichever of its numerous and extremely 

 variable forms it may occur, always bears on its more robust axes short, slightly bow- 



K. Vet. Akad. Handl. Band. 20. N:o 5. 15 



