THE FÜCACEJi: OF JAPAN. 123 



Snt'{/nssuiii niicracanthmn (Kürz.) 

 Plate XV. Fig. 10-21. 



Sargassum {Halochloa) micracanihum wus first established by 

 KüTZiXG from a plant collected in Japan by Tilesius. J. Agardii 

 mentions the same species in Anal. Alg. Cont. III. p. 52, based on 

 material collected in the same place by Kjellman. The specimens 

 which reached both writers were unfortunately sterile and the repro- 

 ductive organ was consequently unknown. There is no little risk in 

 identifying a plant wdth the above named species as w^e have within 

 our boundaries at least three distinct plants, all worthy of specific 

 rank and to all which, when sterile, Kützing's specific definition 

 of the above may be applied equally well : these are Sargassum 

 filicmum Harv., Sargassum kiushianum, and the plant under 

 consideration. The present identification is hence a provisional 

 one, done with the hope that my doubts will be cleared away by 

 some one who has the chance of studying the authentic specimens. 



Among the specimens in our hands, which accord with the de- 

 scriptions by the two writers, there are two well defined varieties, if 

 not species. Kützing's description is more applicable to the one, 

 which I choose to call var. typica; the other, i.e., var. stipulata, 

 has many characters coinciding with J. Agardh's description, 



var, tt/pica Yendo.: Prelim. List of Fuc. Jup. p. 158. 



Plate XV. Fig. 10-17. 



=Halochloa mieracantha Kütz.: Ueber d. Eigeiit. (Bot. Zeitg. 1843) 

 s. 56.— /d: Spec. Alg. p. 633.— /rf.: Phyc. Gen. p. 367.— M: 

 Tab. Phyc. X. Taf. 98. fig. IL 



Description of var. typica. Roots are complanated, disc-shaped, 

 irregularly sinuated at the margin. From the upper surface of 

 the disc there start usually several principal stems which ramify 



