Flora of iwaisima Island Yamagiti Prefecture

The Iwaisima Island is located in the southernmost part of Yamaguti Prefecture. It is 4 km. long and 2.8 km. wide, its area being 7.56 km2. The island has no plains but steep slopes. There are many cliffs facing the sea. It consists of andesite and basalt. The temperature of the island is very warm and the annual rainfall is 1500―1600mm. The forest in the island is almost secondary. The consideration on the analogy with the vegetation of the neighbouring islands leads to conclude that the original vegetation of Iwaisima is to be the association of Castanopsis Sieboldii, Camellia Japonica or Machilus Thunbergii. Excepting the cosmopolitans the plants of this island are showing the type of warm region. Among them Microlepia strigosa, Piper kadsura, Broussonetia papynfera, Paracyclea insularis, Prunus Zipperiana, Sapindus mukorossi, Galarhoeus Jolkini, Actinodaphne longifolia, Xylosma apectis, Actinidia rufa and Canavalia lineata are worthy of notice. Eriobotrya japonica and Trachycarpus Fortunei grow wild in everywhere of this island. Prunus Jamnsakura has considerable number of forms of different colours of flower and young shoot leaves. Morns tiliaefoliti is very abundant in this island and the one grown wild at Miura has the trunk of 2.95 m. in circumference. The list of vascular plants found in this island is mentioned at pages 222―237.