178 KJELLMAN, THE ALGTt; OF THE ARCTIC SEA. 



Callithamnion arbuscula (Dillw.) Lyngb. 



Hydr. Dan. 123. Conferva arbuscula Dillw. Brit. Conf. t. 85. 

 Descr. Callithamnion arbuscula J. G. Ag. Epicr. p. 37. 

 Ficj. « » Harv. Phyc. Brit. t. 274. 



Exsicc. » » Akesch. Alg. Scand. exsicc. N:o 14. 



Syn. Callithamnion arbuscula Kleen, Nordl. Alg. p. 21. 



Hnbitat. The present species grows litoral on exposed coasts, partly on rocks 

 between tides, partly in rock-pools. Occurring often in great raasses, it contributes 

 essentiall)' to mark the character of the vegetation. Kleen states that on the coast of 

 Nordlanden it begins to appear at the beginning of July and develops tetrasporangia 

 already in the same raonth, carpospores in August. It seems to foUow from these 

 statements that the species is annual here. On the coasts of Britain it is perennial 

 according to Harvey, attaining its highest developraent during the summer and the 

 autumn- 



Geof/r. Distrib. Known only from the Atlantic region of the Polar Sea. 



Locnlity: The Norivegian Polar Sea: Nordlanden, common and plentiful. 



Callithamnion roseum (Roth) Harv. 



in Hook. Brit. Fl. 2, p. 341. Conferva rosea Roth, Cat. Bot. 2, p. 182. 



Descr. Callithamnion roseum J. G. Ag. Epicr. p. 39. 

 Fig. » » Harv. Phyc. Brit. t. 230. 



Syn. Callithamnion roseum Kleen, Nordl. Alg. p. 22. 



Habitat. It has been found by Kleen in rock-pools between tide-marks. Taken 

 with tetrasporangia in August. 



Geogr. Distrib. Like the preceding species, this is known only from the Atlantic 

 region of the Polar Sea. 



Locality: The Norwegian Polar Sea: at Givaer in Nordlanden, its most northerly 

 place of growth. 



Callithamnion corymbosum (Sm.) Lyngb. 



Hydr. Dan. p. 125. Conferva corymbosa Sm. Bngl. Bot. t. 2352. 



Descr. Callithamnion corymbosum J. G. Ag. Epicr. p. 40. 

 Fig. » » Harv. Phyc. Brit. t. 272. 



E.vsicc. )> » Aeesch. Alg. Scand. exsicc. N:o 15. 



Sy?i. Callithamnion corymbosum Kleen, Nordl. Alg. p. 21. 



Habitat. It grows scattered on exposed coasts, sublitoral, attached to old shells 

 and deepwater algas, as Deftmarestia acideata, Ptilota pectinata a. o. It attains a consi- 

 derable size even in the Polar Sea. Kleen's collections contain specimens of very luxu- 

 riant growth and a height of even 6 cm. In the Polar Sea it has as 5'et been found 

 only sterile. 



