134 



older ramentum, p. Fig. 6 : inner surface of a rementum viewed 

 from the inside showing two gland-cells, g,g, ^ 2 . Fig. 7 : cross-section 

 of stem, f . Fig. 8 : portion of the same, - 8 ^-. Fig. 9 : longitudinal 

 section of stem, --.' 



Pterosiphonia bipinnata (P. et R.) Fkbg. 



Norn. Jap. : Ito-yanagi. 

 PL CLXXXV, Fig. 1-7. 



Pterosiphonia biphniata Fkbg. Rhod. p. 273 ; Setch. and Gardn. Alg. 

 of northwest. Amer. p. 328; De Toni Syll. IV, p. 997. Po'ysiphonia 

 bipinnata Post, et Rupr Illustr. p. 22. Polyostea zemmiferu Rupr. Tange 

 Ochot. Meer. p. 226, t. 11. 



Fronds filiform, caespitose, soft, setaceous, 5-15 cm. high, erect, 

 throughly ecorticated from the base, distinctly branched below in subdi- 

 chotomopinnate manner and pinnately branched upward. Branches 2-3 

 times pinnate ; in contracted upper portions of branches the arrangement 

 of pinnae is more corymbose (fig. 3), while in elongated ones pinnae 

 alternate on slightly flexuose rachis (fig. 2). Pinnules bend inward at 

 the beginning, afterward becoming turned outward and patent ; the apex 

 of pinnae is almost level-topped with young pinnellae alternately arising 

 from the inside of preceding ones. Pinnae and pinnulae stand on every 

 third articulation, and end in an acute apex from broader base. 

 Articulations in primary filament are shorter below, in the middle 

 portion 3-5 times long as diameter, gradually diminishing in length 

 upward, in upper branches becoming a little longer or shorter than the 

 diameter. Axis is more or less torted with 13-14 pericentral cells. 

 Tetraspores seriated in a longitudinal row in upper pinnae which are 



