34 



tomo-decompound, with erecto-patent branches standing on roundish 

 axils, forming the flabellate outline when spread out on paper. Branches 

 more or less pinnately arranged in an alternate manner with terminal 

 or ultimate segments ending in a little expanded obtuse and slightly 

 emarginate apices. Segments broadly linear, a little expanding in 

 cuneate form beneath forks, 3-7 mm broad, sometimes 10 or more. 

 Margin entire and thickened as if bordered. In the cross-section of 

 frond, cells of the internal layer at the marginal portion are thickend and 

 many layered, instead of being one. Cells of the internal layer are 

 subequal in length and being arranged in somewhat transverse rows, 

 they appear in the surface view as if transversely striated with curved 

 lines extending between both margins. Tetraspores densely scatter- 

 ed over the surface of frond leaving marginal portions sterile, but in 

 some specimens they are seen somewhat to form irregular patches. 

 Colour greenish brown when young becoming more yellowish and 

 darker when old. Substance thick membranaceous and the plant does 

 not adhere to paper in drying. Fruits in summer. 



Hab. : Futae in Amakusa I., Cape Nomo and Hirado (Prov. 

 Hizen), Shinhama (Prov. lyo), Enoshima (Prov. Sagami), Onahama 

 (Prov. Iwaki), Kinkwazan and Karakuwa ( Prov. Rikuzen). 



A new species under the subgenus Slrigocarpus perhaps to be 

 ranked in the vicinity of Dictyota pinnatijida Kuetz. It is easily dis- 

 tinguished by its having thickened margins and stolon-like radical 

 filaments. Though the ramification is more or less dichotomo- 

 pinnate, yet some have an appearence much resembling Dictyota dicho- 

 toma (Huds.) Lamour. 



PL. CVIII, fig. 9. Young frond of Dictyota marginata Okam. 

 n. sp., appearing like Dictyota dichotoma (from Enoshima). 



PL. CIX. Fig. 1 : fully grown frond, \. Fig. 2 : portion of 



