On the Algae from Ogasawara-jima (Bonin Islands). 



By 



K Okamura, Rigahuhdkushi. 

 With pi. L 



The algal flora of this, oceanic island-group seems to be very imper- 

 fectly known at present. Only a few plants have been hitherto known 

 in this part of the Pacific Ocean. Kecently Mr. Heydrich studied 

 Dr. Warburg's collection of algas from Eastern Asia and published a 

 work with the title " Beitrage zur Kenntnies der Algenfiora von Ost- 

 Asien," in which only 4 species, which are already well known, are 

 enumerated. 



I have been for many years very desirous to know about the algal 

 features of the locality referred to, but have had no opportunity to in- 

 vestigate them. A friend of mine Mr. Matsumoto, a physician, took 

 pains to collect some of the algas during his few years' residence in that 

 group, which he preserved in alcohol. He put all his collections at my 

 disposal, thus facilitating my study of the algal flora there. The inves- 

 tigation of those materials was indeed interesting to me and I identified 

 some number of species, among which I found 2 new Caulerpas and one 

 new Caloglossa. Though the number of species studied by me is not 

 numerous, yet they proved somewhat useful in giving information about 

 the distribution of alga? in this part of world. The aspect of marine 

 algas of this island-group is such as may be imagined from its geographical 

 position, many species, quite tropical in their nature, being common to the 

 Australian Sea, the Indian Ocean, &c, as will be seen from the following 

 list. 



CHJLOR OPHYC E AE. 



Ulvaceae. 

 Monostroma T/iur. 

 Monostroma nitidum Wittr.—DE Toni Syllog. Alg. I, p. 100. 

 Hitherto known from : Friendly Islands. 



