114 ART. 12. — K. YENDO. 



fication, however, though in a lesser degree than in this case, is 

 very commonly met with in the fronds of Sargassum. The species 

 next mentioned is an actual example. 



Localities: Esashi and Hakodate, Oshima Prov. (h.h.f.); 

 Zenihako, Shiribeshi Prov. (h.s. a.); Rishiri Isl. (h.h.f.); Cape 

 Soya (h.h.f.), Kitami Prov.; Nikishoro and Chashitsu, Kuna- 

 shiri Isl. (h.h.f.). 



Sfirr/nssiini Thuiiberffii O'Kuntze. 



Plate XV. Fig. 5. 



Eevisio Savg. p. 215.— Id.: Revisio Gen. Plant. III. 2. p. 427. 



= Fucus Thunbergii Meet.: in Roth. Catalect. Bot. III. p. 104. Tab. 



III. fig. a, c-e.— Turn.: Hist. Fuc. Vol. II. p. 158. Tab. 133. 

 = Cijstoscira Thimbergii Ag.: Spec. p. 81. 

 = Rhodomela Thunbergii Ag.: System, p. 199. 

 = Myagropsis Thimbergii Kütz.: Spec. Alg. p. G35. — Id.: Tab. Phyc. 



X. Taf. 93. fig. II. 

 = CystophyUum Thunbergii J. Ag.: Spec. Alg. I. p. 233. — De Toni: 



Syll. Alg. III. p. 153.— M: Phyc. Jap. Nov. p. 47.— Okam.: 



Enumer. Alg. of Jap. p. 140. 

 = Turbin nri a (?) Thunbergii Yendo: Prelim. List of Jap. Fuc. p. 153. 



Remark on the species. The present species is one of the 

 most common algde found at the high tide mark along the coast 

 of nearly the whole of Japan. The colour of the fronds is dark 

 olive-brown, but it turns, except in the vesicles, an intense black 

 on exposure to the air, as is usual with all brown algre which 

 occur between the tide marks. The external appearance of the 

 plant is extremely variable according to its age as well as to 

 the condition of the habitat. The essential characters which give 

 the plants such a divergent appearance are the length of the 

 lateral branches and the internodal distap^e. 



In the embryonal stage of the plant, the principal branches, 



