THE FUOACEiE OF JAPAN. 121 



MICRACANTHJE. 



Receptaculis ovatis, coniplaiuitis, aucipitihii;^, apicc vol margiiie minute 

 dentatis, petiolatis, nunc in axilla lamuloruni solitariis nunc in rainulo 

 contractu aggregatis. 



The following three species present a remarkable peculiarity 

 in the receptacles. The fertile ramulets are always so abbreviated 

 that they arc not able to carry more than three receptacles on 

 each. In extreme cases, only one receptacle, accompanied by a 

 single leaf at its base, represents a fertile ramulet. The 

 receptacles are ovate, ancipitous, excavated on one surface and 

 longitudinally elevated on the other, and minutely spinoso- 

 dentated on the margin or at the apex. The roots are scutate 

 or tuberculate, and the stems mostly angulate ; leaves simple, 

 pinnatisected or entire, with or without cryptostomata ; vesicles 

 coronated wàth a simple leaflet, or often apiculated. 



These species should undoubtedly be included under the sub- 

 genus Bactro]jhycus on account of the undivided receptacles and the 

 other characters. But the dentation on the margin of the complanated 

 receptacles claims for them a systematic position different from the 

 other members. They might better be placed under an independent 

 subgenus if preferred, but I choose to simply mention them in the 

 new section above named under the subgenus Bactrophycus. 



Sargnssiim kiusJiiantini sp. nov. 



Plate XV. Fig. 6-9. 



Diagnosis. Caule , ramis filiformibus, quadrangularibus, longitudine 



striatis, ramulis undique egredientibus ; foliis linearibus, costatis, niem- 

 branaceis, profunde alterne pinnatifidis, laciniis linearibus vel triangular- 

 ibus ssepe apice bidentatis ; vesiculis in petiolo filiformi ipsas sub- 

 ajquaute sj)hsericis, folio pinuatifido coronatis; receptaculis complanatis 

 ovalibus dorso longitudine elevatis, margine minute dentatis, in axilla 

 ramulorum solitariis. 



