1. Twelve species of Citrus described by SWINaLE in 1922 were redescribed here, as the result of the field survey conducted in the Orient and Europe, as well as from the study in the important herbariums of both East and West. A few revisions of the names were proposed. To this list, five hitherto imperfectly known species were added, among which one is new. 2. The greatest ambiguity and weakness of the taxonomy of the genus Citrus so far advanced, were here attributted to the lack of thoroughness in the type conception, allowing too liberal presumption for the origin of type and for the analysis of the distinguishing characters to which the feasibility of species segregation is solely dependent. 3. It was strongly suggested in this paper, that every type, whatever occurring wild or cultivated, should be observed critically as it is in the actual state, without regards of its origin by seeding or by grafting. Characters whioh are unique and specific are the only accessible basis of species determination, and from this point of view, segregation of types of so called "nobilis group" were proposed, as evidenced by the case of C. nobilis, C. deliciosa, and C. unshiu. Equal treatment of wild and garden species was therefore highly recommended under such circumstances. 4. It was also proposed that the garden species thus brought to the rank of the wild species should be named without authority, substituting the term "Hortulanorum" in its stead, as instanced by the name C. unshiu Hort. It was however not recommended to name any definite or presumable hybrid occurring cultivated in the gardens. 5. The concluding scheme of classification of the known Citrus species is shown in the following table: (snip) 6. Further addition to the list will be given as the result of the study now in progress.
世界の柑橘類は其調査未だ完からす。彼のPrunus(サクラ屬)に於けるWILSON及三好の功蹟, Pyrus(梨屬)に於けるDECAISNE及REHDERの事業, Rhododendron(シヤクナゲ屬)に於ける J. G. MILLAIS の事蹟, Iris(ハナシヤブ屬)に於ける W. R. DYKES の大業, Cactus(シヤボテン屬)に於けるROSE及GRIFFITHの貢獻, Nymphaea(スヰレン屬)に於ける H. S. CONARD の大著, Rosa(薔薇屬)に於ける ELLEN WILLMOTTの功労等啻に園藝學上非常の價値を賚したるのみならず, 植物分類上各々 epoch を持來せるものと稱して不可なし。之に對し柑橘に於ては A. RISSO & A. POITEAU の大著 Histoire et Culture des Orangers(1872年版)を以て大成せるの觀あるも, 是歐羅巴に於ける種類の列學に過ぎすして, 未だ世界の柑橘を網羅せりと云ふに足らず。近年 WALTER T. SWINGLE の研究を以って漸く柑橘屬近縁種類の關係稍明瞭となりたるも, 柑橘其者の全世界に渉れる研究に至りては猶考究を重ぬるの要あるなり。茲に著者が第一囘環球探査の結果より得たる一二要項を挙げて此缺を補はんとす。