J Syst Evol ›› 1992, Vol. 30 ›› Issue (1): 1-24.

• Research Articles •     Next Articles

On Some Distribution Patterns and Some Migration Routes Found in the Eastern Asiatic Region

Wang Wen-Tsai   

  • Published:1992-01-18

Abstract: In the present paper seven distribution patterns in west-east direction and eight in southwest-northeast direction found in the Eastern Asiatic Region (Taxta ЛЖЯΗ 1978) are discerned,and the taxa belonging to each of these patterns are enumerated. Some of these taxa are analysed geographically or/and phylogenetically. Clematis brevicaudata and C. ganpiniana,Aconitum sinomontanum var. sinomontanum and A. sinomontanum var. angustius, Thalictrum alpinum and T. squamiferum, Adonis brevistylus and A. sutchuenensis, Ostryopsis davidiana and O. nobilis, Corylus heterophylla var. heterophylla and C. heterophylla var. sutchuenensis, C. ferox var. ferox and C. ferox var. tibetica, Carpinus cordata and C. fangiana, Cyclobalanopsis glauca and C. glaucoides, Decaisnea fargesii and D. insignis, Elatostema obtusum and E. medogensis, Corylus sect. Corylus and sect. Acanthochlamys, Prinsepia sect. Prinsepia and sect. Plagiospermum, Corylus and Ostryopsis, Hilliella and Yinshania (Zhang 1986, 1987), ,Actinidia and Clematoclethra (Tang and Xiang 1989), Peracarpa and Homocodon (Hong 1983) etc. are all regarded as sister groups and might have differentiated in Southwest China. According to the geographical distribution and the affinities, the following taxa might be considered to have originated in Southwest China: Salix wallichiana, S. paraplesia and S. cheilophila (Zhou, Fang et al. 1984),Aristolochia debilis (J. S. Ma 1989),Aconitum hemsleyanum (L. Q. Li 1988), Semiaquilegia adoxoides (Hsiao et al. 1964), Dichocarpum adiantifolium (D. Z. Fu 1988), Thalictrum baicalense, T. alpinum var. elatum, Anemone flaccida, A. baicalensis, A. hupehensis, A. tomentosa, Clematis henryi, C. lasiandra, C. montana, Corydalis curviflora, Chrysosplenium griffithii, C. uniflorum (Pan 1986), Parnassia foliosa (Ku 1987), Tetrastigma obtectum (Gagnepain 1911), Actinidia kolomikta, A. polygama (Liang 1983, 1984), Incarvillea sinensis (Grierson 1961), Paris polyphylla (H. Li et al. 1988), etc.. The genera Dichocarpum (D. Z. Fu 1988),Loropetalum, Corylopsis (Harms 1930; Chang 1979), Stachyurus (Chen 1981; Tang et al. 1983), Helwingia (Hara and Kurosawa 1975), Aucuba (Hara 1966;Soong 1982;X. W. Li 1987), Enkianthus and Cardiocrinum (Kanai 1966) with the typical eastern-Asiatic distribution pattern and with either the distribution center or the primitive group in Southwest China are also considered to have arised there. According to the fact that the distribution centers of the genera Elatostema (Wang 1980), Hemiboea (Z. Y. Li 1987), and Lysionotus (Wang 1983) are situated in southeastern Yunnan and western Guangxi, Elatostema involucratum, Hemiboea henryi, and Lysionotus pauciflorus might originate there and from there migrated northeastewards to East China or Japan respectively. On the basis of the 15 distribution patterns and the analyses just given, three migration routes may be recognized, i. e. (1) the route extending from Southwest China eastward along the Qinling Range and the Dabie Range in the north, which may be named as the Qinling-Dabie Corridor, along the Nanling Range in the south, which may be named as the Nanling Corridor, and along other mountain chains in Central China to East China or Taiwan province of China, and eventually to Japan, (2) the route running from Southwest China westwards to the Himalayas, which has been named as the Himalayan Corridor (Kitamura 1955), and (3) the route stretching from the Hengduan Mountains northeastwards through the Qinling Range, the eastern fringe of the Loess Plateau including the Taihang Range, the Yinshan Range, the Changbai Mountains and the Xiao Hinggan Mountains to Siberia or/and the adjacent regions. The last route may be named as the Chinese southwest-northeast Corridor, being the passage for various floristic elements migrating from Siberia or Northeast China southwestwards to Southwest China and vice versa during the Quaternary Ice Ages (Wang 1989). According to the geographical distribution of Hemiboea henryi and Lysionotus pauciflorus (Gesneriaceae, Wang Fig. 2, 1983), that of Chirita anachoreta and Aeschynanthus acuminatus (Gesneriaceae, Wang, Fig. 5, 1985), that of Chirita pumila, Lysionotus serratus, Aeschynanthus superbus, A. bracteatus, Rhynchotechum vestitum (Gesneriaceae, Wang, Fig. 2, 1983, 1985), Elatostema laevissimum, E. balansae, E. macintyrei (Urticaceae, Wang 1980), Tetrastigma serrulatum (vitaceae, Wang 1979), and Alcimandra cathcarthii (Magnoliaceae, Wu and Wang, Fig. 1, 1957), that of Euchresta (Leguminosae), Bennetiodendron (Flacourtiaceae), Rhopalocnemis phalloides (Balanophoraceae, Steenis, Fig. 4, 1935; Wu and Wang, Fig. 6, 1957), Thalictrum javanicum (Ranunculaceae), Elatostema backeri, Chamabainia cuspidata, and Droguetia pauciflora (Urticaceae, Wang 1989), and that of Caryodaphnopsis (Lauraceae, Wu and Wang, Fig. 5, 1957; H. W. Li 1979), distinguished may be additional five migration routes, i. e. (1) the route extending from southeastern Yunnan and western Guangxi northeastwards to East China and Japan, (2) the route running from the southern Yunnan-Guizhou Plateau eastwards along the Nanling Corridor to Taiwan province of China, (3) the route stretching from the southern Yunnan Plateau and the northern Indo-China westwards along the southern and western margins of the Yunnan Plateau to southeastern Xizang (Tibet) or/and Assam, and along the Himalayan Corridor eventually to Nepal, (4) the route extending from the same regions just mentioned southwards through the Malayan Peninsula to Sumatra and Java, and (5) the route stretching from the same regions also southeastwards through Borneo to the Philippines. The analyses and the radiant pattern of the migration routes mentioned above lead me to agree with the important arguments that in Southwest China “the important parts of the original flora of China evolved”, and “the Sino-Himalayan region has the richest alpine flora of the world” (Li, 1944), that the Chinese flora without any doubt, is not only the foundation of the other floras of eastern Asia, but also the origin of many floristic elements of temperate regions (Wulff, 1944), and that the flora of South and Southwest China and the Indo-Chinese Peninsula, being most rich in archaic families and genera and being derived from the palaeotropical flora, has given rise not only to the temperate and subtropical floras of eastern Asia, but also to those of North America and Europe (Wu, 1965). The facts that in Yunnan Province occur about 2110 genera and 13900 species of the angiosperms (Wu et al. 1984; H. W. Li 1985) and in the Hengduan Mountains “no less than 1500 genera and perhaps more than 10 thousand species” (Wu 1988), and that located in Southwest China is the center of endemism of China (Ying and Zhang 1984; H. S. Wang 1985), and the palaeobotanical evidence that the temperate floras appear to have differentiated by the Middle Cretaceous (Berry 1937; Axelrod 1952; Takhtajan 1969), further lead me to speculate, though in the absence of fossil data, that the Yunnan-Guizhou Plateau plus Sichuan Province might be an important center of development of the angiosperms in the Northern Hemisphere once by the Middle Cretaceous and a strong evolutionary radiation might have taken place there, which resulted in the formation of the migration routes described above from this center to various regions in various direc-tions.

Key words: Distribution pattern, Eastern Asiatic region, Migration route, Center of development, Angiosperms