— 131 — 



slightly swollen upwards, and are neither falcate nor pointed, but 

 very patent, straight and very obtuse at apex. The bases of ra- 

 menta are sometimes equally broad or a little narrowed as if pe- 

 dicellated". The ramuli reach "a length of 216—354//; the shorter 

 one half that amount". "The portion of rachis intercepted between 

 two opposite ramenta is slightly constricted as if articulated; it is 

 more especially so in frond bearing ramenta constricted at base. 

 In frond bearing ramenta which are not narrowed at base, the 

 constriction of rachis is not so marked". From this it seems 

 clear that our plant is very different from this form, as a 

 glance at the figure quoted in Okamura's paper will quickly 

 show. 1 ) By reason of the constricted or articulated rachis Oka- 

 mura also refers his plant to the group Sedoideæ and in M me 

 Weber van Bosse's Monograph we therefore find Caulerpa am- 

 bigua in the subgroup IV Opuntioideæ of the section Sedoideæ. 

 In Caulerpa Vickersii the rachis is not constricted and as mentioned 

 above I think our plant is most nearly related to Caulerpa fasti- 

 giata; in the "Phycologia Barbadensis" M lle Vickers has placed 

 it between C.fastigiata and C.pusilla and I think this is more than 

 a mere chance. 



In addition to what I have just said with regard to C. ambigua, 

 I may add a word on the supposed greatest peculiarity of this 

 plant, namely the lack of rhizome. In the diagnosis of the plant 

 Ok a mur a has described it in this way: "Frond dwarf, filiform, 

 isolated with no repenting surculus, erect, rooting downward . . .", 

 but in the more detailed description Okamura expresses some 

 doubt on the matter and mentions that he has only had very little 

 material; in the specific name ambigua also I think the author has 

 hinted this doubt. Having now examined the above-mentioned 

 specimen in "Algæ Japonicæ Exsiccatæ", this seems to me very 

 clearly to show a rhizome. Quite in accordance with what I have 

 found in my plant the rhizome was very irregularly bent and rami- 

 fied, often bore ramuli and seems in all not to be much differentia- 

 ted. Upon the whole I may point out that as to the rhizome 



*) In "Algæ Japonicæ Exsiccatæ" nr. 95 a specimen of this species is distribu- 

 ted. Judging from the material at hand (very little material is present) 

 I think we have to do with the above-mentioned form, the first named 

 by Okamura. As to the essential character, the constriction of the 

 rachis, this of course is always more indistinct in dried material but never- 

 theless I think I have been able to see a trace of it. 



9* 



