著者

村田 源 小山 博滋

出版者

国立科学博物館

雑誌

国立科学博物館専報 (ISSN:00824755)

巻号頁・発行日

no.9, pp.p111-121, 1976-10

被引用文献数

4

---

The "Sohayaki element" was defined by the late Dr. Gen-ichi KOIDZUMI in 1931 as one of the important floristic elements of Southwest Japan, and 101 species of vascular plants were enumerated by him as the components of the element (in MAYEBARA, 1931). Since then, several investigations have been attempted to clarify the entity of the present element. It is now regarded as one of the most ancient flora of Japan. No one, however, has reevaluated the species enumerated by KOIDZUMI. Having the specimens deposited in the herbaria of Kyoto University (KYO), University of Tokyo (TI), Tokyo Metropolitan University (Makino Herbarium-MAK) and National Science Museum, Tokyo (TNS), the flowering plants cited by KOIDZUMI as the components of the "Sohayaki element" are studied in this paper from taxonomic and phytogeographic point of view. The phytogeographic significance of the present element is also discussed. As shown in Table 1,the following five groups are recognized in the "Sohayaki element" by the distribution pattern of each species. The distribution maps, based on the specimens kept in the herbaria cited above, are drawn by the KLIPS-C computer system designed by Dr. H. KANAI, National Science Museum, Tokyo. I : The plants are distributed in the Sohayaki region which includes Kii Peninsula, Shikoku and Kyushu (as shown in Fig. 1), though they are divided into 5 subgroups(A-E). The plants belonging to the subgroups of B, C, D, and E are distributed in rather narrow area than those of A. II : The plants are distributed only in the West Japan as shown in Fig. 2. III : The plants are distributed in both West and East Japan, though they are divided into 5 subgroups (A-E). Distribution areas of B and C are shown in Fig. 3 and 4,respectively. IV : The plants are distributed from the Sohayaki region in West Japan to rather north area in central Honshu as shown in Fig. 5. V : The plants are distributed from Japan to Northeast China throughout Korean Peninsula. VI : The plants are widely distributed in both Japan and the Chinese Continent. KOIDZUMI also described the following elements with the enumeration of the species, i.e. , "Central Chinese element : 51 spp.", "Kuma-Kanto element : 22 spp.", "Manchuria-Korean element : 38 spp." and "Chugoku element : 27 spp.". The "Kuma-Kanto element" was considered as the plants endemic to the areas from Kyushu to Kanto district of Honshu, and the "Chugoku element" as those endemic to the Chugoku district of Honshu. Judging from his definition of each element and the distribution patterns summarized in Table 1,B and C of III are considered as the "Kuma-Kanto element", V is recognized as the "Manchuria-Korean element" and VI as the "Central Chinese element". I and II in Table 1 are the Sohayaki elements which are now generally recognized. The Sohayaki elements occur in the area of warm temperate zone from about 200m to 800m in altitude and are minor constituents in the present vegetation. The habitat of the elements is usually restricted within the limestone or serpentine areas, in rocky places near the river which often overflows and in the ill-nourished or dried places of mountain ridges. These facts suggest that the present elements, protected from extinction by the habitat mentioned above, have survived for long time in competition with the invaders of both glacial and interglacial period.