The genus
Coriaria, the one of the archaetypic angiosperms, has very peculiar distributional areas (Fig.1), and it is noteworthy that these areas can be nearly included in the girdle along the one of the great circles of the globe (Fig. 2). In this day there is good proof, from the palaeo-magnetic studies, of the pole wandering and the continental drift in the past. Beside this, the author accepts the hypothesis in which the new large groups of plant have been usually originated in tropical and/or subtropical montane regions and the angiosperm also is not the exception. With the aids of these conceptions, the author realizes that the present
Coriaria's areas are the remnant scar of its aboriginal distributional range where the genus had started and developed but later discarded principally by the continental drift in the new world and disjuncted through the extinction induced by the enlargement of desert areas in the western and central parts of gerontogea and also by the development of the ice-covering. This palaeotropical and palaeosubtropical montane girdle, I should say, had covered the large areas, from South America to New Zealand, through in sequence, eastern North America, western North Africa, Europe, northern Central Asia, South-eastern Asia and Melanesia and had been the starting bed of probably most of the ancestors of the recent angiosperm, which might be expected to start there already as early as the later Palaeozoic Era.
Lardizabalaceae (Asiatic monsoon area and Chile) and
Mitrastemon (SE Asia and Mexico-Guatemala) are the other good examples. Eastern Asia (Himalaya-Sino-Japanese element) and Eastern North America (Appalachian element) are famous with having in common many temperate genera of old type and the author considers that they surely belong to the same category.
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