170 KJELLMAN, THE ALG OF THE ARCTIC SBA. 
Ceramium rubrum (Hups.) Aa. 
Disp. Alg. p. 16. Conferva rubra Hups. Fl. Angl. p. 600. 
f. decurrens J. G. Aa. 
Spec. Alg. 2, p. 127. 
Descr. Ceramium rubrum @ decurrens J. G. Ac. Epier. p. 100. 
Kasice. » decurrens Argscu. Alg. Scand. exsice. N:o 208. 
f. genuina. 
f. interstitiis et juvenilibus et adultis densius corticatis; ramis lateralibus paucis, conformibus, dichotomis. 
f. prolifera J. G. Aa. 
Spec. Ale. 2: p. 12% 
Deser, Ceramium rubrum # proliferam J. G. Ac. Epier. p. 100. 
Fig. » secundatum Lynes. Hydr. Dan. t. 37 A. 
» botryocarpum Harv. Phyc. Brit. t. 215. 
f. pedicellata Duy. 
sec. J. G. Aa. Spec. Alg. 2, p. 128. 
Descr, Ceramium rubrum 1) pedicellatum J. G. Ac. Epier. p. 101. 
Fig. » » Kurz. ‘Lab. Phye: 13, t- 45 fiesa. et (b: 
f. squarrosa Harv. 
Ner. Am. 2, p. 214. 
Deser. Ceramium rubrum e. squarrosum Harv. l. ec. 
Fig. » » f. squarrosa tab. nostra 15, fig. 7. 
Syn, Ceramium rubrum J. G. AG. Spetsb. Alg. Progr. p. 2; Bidr. p. 11. 
» » Croat, Fl. Dise. p. 460. 
» » Gost, Algenfl. Weiss. Meer, p. 46. 
» » KJELLM. Spetsb. Thall. 1, p. 25; Algenv. Murm. Meer. p. 23. 
» » Kuen, Nordl. Alg. p. 20. 
» » Nyl. et Sal. Herb. Fenn. p. 74. 
» » virgatum Post. et Rupr. Ill. Alg. p. II. 
Conferva diaphana We. Fl. Lapp. p. 511. 
Remark on the definition of the forms. Ceramium rubrum, in the Polar Sea as well 
as elsewhere, is multiform. The rather few specimens from the former region which 
I have had the opportunity of examining, appear however to be referable to the above- 
mentioned forms. The specimens determined by me as being f. decurrens are in all 
essential points similar to those from the northern portion of the Atlantic. This form 
is easily known by its articular cells being at first uncorticated, by the absence of 
prolification and by its poverty in lateral branches, which, if existing, branch in the 
same manner as the main axis. Besides, the frond is more strongly attenuated upwards 
than in any other form. The form designated by me as f. genuina resembles the former 
in habit, branching etc., but differs from it by its darker colour and the strongly 
corticated articular cells. Nearest this there stands a robust and large-sized form, well 
represented by fig. a, table 4 in Ktrzme’s Tab. Phye. 13 and certainly belonging to 
the same series of forms of Ceramium rubrum as the plant figured pl. 181 in Harv. 
