iw.] ON THE DISTRIBUTION OF THE FORMOSAN CONIFERS. .39 



Structure of the Liukiu (Loo-choo) Curve, and its Kelation to the Northern 

 part of Formosa, l >" states that the northern part of Formosa and Saki-shima 

 group, the south west end of the curve, are very similar in their geological 

 characters, i.e. — they have many coal-seams of the same character, and 

 characteristic fossils, such as Echinodiscus, Pecten &c, found in the Miocene. 

 He also told me that he has well grounded suspicion that Formosa and 

 Japan had been connected until the Miocene age by a land mass. 



And if we admit Dr. Koto's affirmation as to the former existence 

 of the very east extremity of the Asiatic bank, to which, I think, belong 

 Japan and Formosa as well as Liukiu, we have also a good geological 

 reason to divide the Chino-Japanese Flora into the two, beside the botanical 

 reasons. 



Upon considering all these cases, I agree with some geologists in the 

 following conclusion : — 



Japan and Formosa had been connected by a land-mass which now 

 partly remains as Liukiu Islands. 



IV. Summary. 



In the course of my study of the Formosan flora, I found that there 

 is a very peculiar similarity between the Japanese and Formosan. This 

 rendered me to wonder if there had not existed a land mass between 

 Japan and Formosa ; because the similarity of flora is much more affected 

 by the continuation of land than any other physical condition. I have 

 chosen here the Coniferae as an example, as conifers are a comparatively 

 old type and are restricted in each locality, and therefore, very convenient 

 for the observation of the relation of flora. 



Studying the Conifers in the Asiatic flora, I found that the Chino- 

 Japanese flora is naturally divided into two florules i.e. — 1) Border Florule, 

 2) Central Florule. The two originate in North China, one developing in 

 the central part, and forming the Central Florule, and the other developing 

 in the border region and forming the Border Florule. 2) 



I found also that the conifers of Formosa are much more similar to 

 those of Japan than those of Central China, and I have come to the con- 



1) Journ. Coll. Sci. Imp. Univ. Tokyo, Vol. XVI, Art. 2. 



2) After completing this work, I have had the opportunity of reading the extract of 

 Dr. L. Diets' "Die hochalpinen Floren Ostasiens" (Fest-schrift fiir Paul Ascherson. Leip- 

 zig, Gebr. Borntraeger, 1904. p. 487-499.) in " Botanisches Centralblatt." Bd. XCVIII. Nr. 

 7. — 1905. He discussed the floral formation of the alpine plants and came to the almost 

 •same conclusion as I have got from the study of the conifers. 





