r,0 THE r.OTAl^ICAL MAGAZrS'K. [Voi. xxx. No. a-,o. 



Porphyra leucosticta Thuret. 



in Le Jolis : List. Alg. Alar. Chcrb., p. 100.— J. Ac: Till Alg. 

 System. VI, rp- 64, Tab. II, fig. 55-59.^anczews.: Etud. Atiatom. 

 I'orphy. P1._XIX, fig. 1-14. — Bkrthold: Baugiac. p. 24, Taf. I, 

 fig. 1-6.— Ardiss.: Phyc. Medit. I, p. 46S.— De Toni et Levi: Plivc. 

 Ital. No. 18.— Collins: Notes on Algae. V, p. 211 (Rhodora Vol. ">, 

 1903).— Rusexvenge : Mar. Alg. Denmark, Part I, i). 65, fig. 7. 

 — Porphyra ixtropurpurea De Toni: Syll. Alg. IV, ji. 17. 

 . — XJlva atropurpurea Olivi : in Saggi Acad, di Padova, III, i, ]>. 

 153, Tav. 1-3 (sec. De Toni). 



(for other referrences, see : De Toni, I.e.). 



However the specific limitations of Porphyra are not 

 sharply delineated, it appears to me that the localizntion of 

 the antheridial cells in the streak-form patches within the 

 carpogonal, is a constant and reliable character for specific 

 distinction. Porphyra leucosticta Thur. may be taken as a 

 type, of such form. Some early writers who have put greater 

 importance to the general outline, colour, or habit of frond, or 

 to the thickness of blade or size of cells, seem to have identified 

 the plant what we now call under P. leucosticta Thur. to 

 various diflferent species. As far as I could ascertain, there are 

 four specific names given to different forms of plant which 

 belong to the category of P. leucosticta Thur. They are: — 



P. leucosticta Thur. North Atlantic. . 



P. clongata Kylin. West coast of Sweden. 



P. suborhiculata Kjellm. Japan. 



P. tenera Kjellm. Japan. 



The specimen distributed as Phyc. Bor.-Amcr, No. 37G 

 under P. leucosticta seems to me to differ greatly from the 

 ordinary form of the species in important characters. In it 

 the antheridial streaks run parallel to the margin of frond, 

 and not obliquely wedging inwards from the margin. It is 

 perhaps a new species, belonging undoubtedly to the same 

 category with P. leucosticta Thur. 



The mentioned four species were synoptically divided as 

 follows : — 



