AN ANALYTICAL STUDY OF THE MARINE ALGAL FLORA OF THE WESTERN YELLOW SEA COAST II. PHYTOGEOGRAPHICAL NATURE OF THE FLORA
1964; Linguagem: Inglês
ISSN
0029-814X
Autores Tópico(s)Marine and coastal plant biology
ResumoThe marine algal flora of the Western Yellow Sea coast has been compared with those of the neighboring regions on different bases.1. First of all, the comparision has been made on the bases of both generic and specific similarity indices. The similarity index of two floras as defined by Szymkiewicz is represented by a numeral obtained by dividing the number of non-cosmopolitan genera (or species) common to both floras by the number of non-cosmopolitan genera of the poorer flora, i.e. the one with lesser number of genera; when the similarity index is 0.50 or more, the two floras involved are regarded as being closely related to each other. Comparision made on this basis shows that the marine flora of the Western Yellow Sea coast is closely related to those of the Japan Sea and the Japanese Pacific coast, especially that of the Southeastern Japan Sea coast. Relationship of this flora with those of the Southwestern Ochotsk Sea and of the South China coast has also been noted.2. Components of the Western Yellow Sea coast marine algal flora have been grouped on the basis of their phytogeographical nature. Of the 165 macroscopic species, 91 or about 55.2%, are of boreal nature. The remaining species are of various nature, of which 43 species, amounting to 26.1%, are boreal-austral, of the others being boreal-arctic and boreal-austral-warm water species. It is evident that practically all species are boreal or boreal-mixed in nature. Hence it is suggested that the algal flora of the Western Yellow Sea coast belong to the Boreal floras.3. Sixty eight species are endemic to the Western North Pacific. Beside 8 species which are so far endemic to the Western Yellow Sea coast, the remaining 60 species have been analyzed on the basis of their distribution in this vast area.These species are all found in the Japan Sea and in accordance with their distribution in this and neighboring regions, may be divided into 3 groups. The northern group consists of only 4 species, which are mainly distributed in the northern coasts of the Japan Sea and Pacific Japan, extending to as far as the northern Ochotsk Sea or even Western Bering Sea. On the China coast these are found only in Western Yellow Sea, principally on the North Yellow Sea coasts. The southern group consists of 21 species which are mainly distributed on the southern coasts of the Japan Sea and Pacific Japan, extending southward to the northern islands of the Riukiu Islands or even the southern parts of the South China Sea. On the China coast, many of these species are distributed southward to the East China Sea and South China Sea coasts. The remaining 35 species are intermediate in nature, constituting the central group, which are mostly found within the Japan Sea, some extending to the Japanese Pacific coast and the southwestern Ochotsk Sea, the floristic nature of which is more related to that of the Japan Sea than that of the northern and southeastern Ochostsk Sea. Thus the close relationship between the marine flora of the Western Yellow Sea coast and that of the Japan Sea coast is herewith further revealed. It is of interest to note that these species, endemic to the Western North Pacific, with very few exceptions, are not found in the central and southern Riukiu Islands and Taiwan, indicating their different floristic nature.4. The distribution of 4 species is worth mentioning. The occurrence of Cystophyl-lum caespitosum and Tsengia nakamurae is so far restricted to the Western Yellow Sea and Japan Sea coasts. Two boreal-austral species, namely Solieria mollis and Dasya villosa are also found, in the northern Pacific, only in Western Yellow Sea and the Japan Sea. This strengthens our belief that the marine flora of the Western Yellow Sea coast and that of the Japan Sea coast are very closely related to each other.5. Five genera, namely, Undaria, Tsengia, Hyalosiphonia, Campylaephora and Ardis-sonula which are endemic to the western north Pacific, are also represented in the Western Yellow Sea algal flora. The genus Undaria is not a native of the Western Yellow Sea, being intr
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