Flora of the Manzyu-and the Kanzyu- Islands, Yamaguti Prefecture

The Manzyu- and theKanzyu-Islands are located in the Sudnada Sea of the Inland Sea Region, and belong to Simonoseki City. They have been theposession of thelminomiya Shinto Shrine from olden times, and sacredly preserved　in natural condition without any dwellings or dwellers. They are now legally protected by the National Law as the Natural Monuments. The Manzyu-Island has an area of 7,403㎡, and the Kanzyu Island 41,518.9㎡. The highest point of the former island is 13m above sea level, and that of the latter island is 49.6m. The northern shore of the islands generally sandy, while the other parts are rocky. They all consist of granite rocks. The climate is not of the Inland Sea type, but of the Northern Kyusyu type. The annual mean temperature is 16.3℃, and the annual rainfall is 1,626.5mm. The strong wind prevails in this district, especially in August. The dominant species of the forest in the islands is difficult to be determined, because the islands are too small in area and the strong wind controls the normal development of the vegetation. On and around the summit of the Kanzyu-Island Castanopsis cuspidata SCHOTTKY is abundantly found, and Camellia japonica LINNAEUS var. spontanea MAKINO grows luxuriantly near the summit of the Manzyu-Island, though the natural climax of the latter island is supposed to be the association of Ilex Integra THUNBERG from the considerations on the result of quadrat survey. In the Kanzyu-Island the luxuriant growth of Distylium racemosum SIEBOLD et ZUCCARINI is recognized at the northern steep slope. All the plants grown in these islands are of warm region type. Among them Podocarpus macrophylla D. DON, Piper Kadsura OHWI, Cudrania cochinchinensis KUDO et MASAMUNE, Ficus pumila LINNAEUS, Fiwa japonica J. F. GMELIN, Rubus ribisoides MATSUMURA, Prunus Zlppeliana MlQUEL, Evodia ^ZawcaMlQUEL, Galarhoeus Jolkini HARA, Celastrus punctatus THUNBERG, Actinidia ruja PLANCHON, Osmanthus Zentaroanus MAKINO, Gardneria nutans SIEBOLD et ZUCCARINI, Anodendron ajfine DRUCE, Carex Matsumurae FRANCHET and Ophiopogon Jabvran LODDIGES are especially worthy of notice. The Kanzyu-Island is a unique locality of Osmanthus Zentaroanus MAKINO in the Inland Sea region, and this fact indirectly shows the evidence that the flora of the island does not belong to the Inland Sea type. As for the flora of the islands, T. Oda in 1910 described 86 species of plants, and M. MlYOSHI in 1926 mentioned 65 species from the Kanzyu-Island and 26 species from the Manzyu-Island. In 1930 S. NAGATOMI found 64 species of plants in the islands. The writers described 203 species of vascular plants grown in the islands, and the results of their survey are briefly tabulated as follows:-