276 THE BOTANICAL MAGAZINE. [Vol. xxix. No. m. 



Distribution and affinities. 



Of the three species Undaria pinnatiGda has the widest range 

 of distribution, of which the reader will get some idea from 

 what has been mentioned above under the localities of that 

 species. It is found in the warmer districts from Kyushu to 

 almost northern extremity of the western coast of Hokkaido, 

 where is a warm current known as " Tsushima current " in the 

 Japan Sea. In the districts washed by the " Kurile current " 

 (cold) as well as the " Kuroshiwo " (warm) it does not grow; 

 hence it is not found in the localities projected in the southern 

 part such as Prov. Shima and Prov. Kii where the " Kuro- 

 shiwo " frequently visits. Also it is not known in Hokkaido 

 along the coast north-east from Mororan where the " Kurile 

 current " flows. 



Undaria Peterseniana and U. undarioides have almost an 

 equal range of distribution, but that of the former is wider 

 than that of the latter as far as the present knowledge goes. 

 The former is found up to about half way of both coasts of the 

 Main Island from south, while the latter is not known in the 

 Japan Sea. I have a specimen from Prov. Iki (an island in the 

 west of the Japan Sea) which is doubtful to be determined as 

 either one of the two. The two species are found at the same 

 place in Prov. Boshyu, but the latter, there, is rather rare, 

 so that this species may be said to prefer warmer part than 

 the former. At present Undaria undarioides is known to be 

 aboundant^ collected in Provinces Shima and Kii where the 

 other two related species do not grow. From the two south- 

 wardly-projected parts of Shikoku neither Undaria Peterseniana 

 nor U. undarioides are known, but in future either one or both 

 will perhaps be detected. Taking the distribution into considera- 

 tion it may be said that the three species of the endemic genus 

 Undaria have developed within our warmer waters in the north 

 Pacific. 



Let us in the next place consider the affinity of this genus 

 with others and phylogeny of the three species. It will be 

 beyond any doubt that Undaria Peterseniana and U. pinnatiAda 



