Marine Algce of Berwick-on-Tweed. 307 



Class IV.-EHODOPH YCEtE. 

 Order VII.— FLORIDEiE. 



Family— P orphyracese. 

 PORPHYRA, Ag. 



(Laver, slake, slocatjm.) 



porphyra coccinea, j. ag . 



(Mscr. 1836) Till. Alg. Syst. vi., p. 56. 

 Descr. Porphyra coccinea, J. Ag., i.e. 

 Fig. „ „ J. Ag., i.e. pi. II., fig. 41, 43 ; Aresch., Phyc. 



Scand. Mar., p. 181, tab. 1, D. (sect, transv.) 

 Exsicc. Porphyra minima, Crouan, in Desmaz, Exs., ser. 2, no. 612. 



Porphyra delicatula, Wehv., PI. Lusit., no. 293. 

 Syn. Porphyra coccinea, J. Ag., Nov. PI. Suec, p. 6 (sine descr.) 



Porphyra minima, Crouan, Fl. Finist., p. 132. 

 Hub. On a specimen of Halidrys siliquosa cast ashore from deep water. 



Very rare. Berwick Bay. 

 A pretty little, bright-coloured species. The fronds which are 

 very delicate and easily torn, are from a quarter to one and a half 

 inches in diameter, sessile, oval or roundish in outline, the margins 

 more or less crisped. The cells composing the frond are very 

 minute, a circumstance which serves to mark the species. 



Porphyra leucosxicta, Thur. 



in Le JoL, Liste Alg. Mar. Cherb., p. 100. 

 Descr. Porphyra leucosticta, Le JoL, I.e. 

 Fig. „ „ J. Ag., Till. Alg. Syst. vi., p. 64, pi. n., fig. 



55-58. 

 Exsicc. Porphyra laciniata, Crouan, Alg. Finist., no. 397 (uon Ag.) 

 Porphyra leucosticta, Holmes, Alg. Brit. Rar., no. 46. 

 Porphyra vulgaris, Rabenh., Alg. Sachs., no. 900; Lloyd, Alg. 

 de l'Ouest, no. 7 ; Erbario Orittog. Ital., no. 278 (non Harv., nee. 

 Crouan.) 

 Rab. On rocks and Algae from half-tide level to low-water mark. Dec. 

 — June. Not uncommon. Berwick Bay, Scremerston, Holy 

 Island, and elsewhere along the coast. 

 Easily distinguished from Porphyra laciniata by the position of 

 the antheridia which form yellowish-white patches within the 

 margin of the frond, and not a marginal zone as in that species. 



