1984, 22 (1): 1–5
(1) Many plants in eastern China are conspecific with those in Japan,for example, Cercidiphyllum japonicum, Magnolia sieboldii, Lindera praecox, Kirengeshoma palmata, Platycrater arguta, Oxalis obtriangulata, Orixa japonica, Ilex porpurea, Acer nikoense, Meliosma myriantha, Eurya japonica, Styrax obassia, Comanthosphace japonica, Rabdosia longituba, Mitchella undulata, Croomia japonica, Cypripedium japonicum, Galeola septentrionalis etc. Especially, Peltoboykinia tellimoides and Petrosavia sakuraii were formerly considered
as being confined to Japan and Yoania japonica as distributed only in N. India and Japan, but
the specimens of these species have recently been collected from Jiulong-shan in Zhejiang
(2) Though the genera Cunninghamia, Glyptostrobus, Metasequoia, Liriodendron,
Sassafras, Liquidambar etc. existing now in eastern or central parts of China are extinct from
Japan, the fossils of leaves, fruits or seeds of Cunninghamia protokonishii, Glyptostrobus
europaeus, Metasequoia glyptostroboides, Liriodendron honshuense etc. have been discovered
from Japanese Tertiary Strata, which seems to indicate that the floristic relationship between Japan and eastern China was closer in ancient time than it is now.
(3) The fact that some species in Japan have close relatives in Nepal, Sikkim or Bhutan may suggest that the western edge of the Sino-Japanese Floristic Region extends probablyto the Himalayan corridor.