Pachydictyon coriaceum (Holmes) Ok 風 



Norn. Jap. : Sanada-gusa, 

 PL. XXIII， Figs. 1-6; PL. XXIV, Figs. 6-12. 



Pachydictyon coriacewn (Holmes) Okani. Contrib. Know!. Mar. 

 -.Alg. Jap. Ill, p. 13 (Bot. Mag. Tokyo 植物 學雜 誌， Vol. XIII, 1899, 

 No. 145, p. 39) pi. I, fig. 31-34 ； 村， ri 本 藻 Si 名 p. 112.— 

 Glossoplwra coriacca Holmes New Mar. Alg. Jap. no. 5 in Jouni. Linn. 

 Soc. Bot. Vol. XXX， p. 251. 



Fronds 30-40 cm. hip-h, dichotomo-decompound, shortly stipitate 

 and stupose at base. At a height of some 3-4 cm. above the base, the 

 frond beo-Ins to divide repeatedly in cllchotomous manner, the ramifi- 

 cation beincr more or less fastii^Iato-flabellate. Se^rnents are linear- 

 cuneate, 7-15 mm. broad, with round axils and entire margin ； they are 

 usually separated by remote forks, but sometimes they approach much 

 nearer to each other. Terminal se〔rments are lio-ulate and end in 

 either a rounded or bilobed apex, the lobes being mostly parallel or 

 a little patent. Many proliferous sep^ments are produced mostly from 

 injured ends of older segments. 



" In the older portion, the frond evidently consists of three layers 

 of cells. The Inner layer consists of large cells, disposed in a single 

 layer extendinp- between both marp^ins ； here and there some of them 

 are divided into two by a partition parallel to the surface. The wall 

 of cells is very much thicker in older than in younijer portions. 丁 he 

 epidermis consists of a layer of cubical or low rectangular cells, sub- 

 equal to the* breadth or twice as long as broad. They are arram ァ ed 

 111 a Ion リ 'itudinal row, as seen in surface view. Below the epidermis 

 ； here is one or more layers of small cells, which are sliphtly lanjer 

 than the epidermal, but much smaller than the cells of the inner layer 



