This paper is the main part of a Ph. D. thesis accepted by the University of Tokyo (Akiyama, 1985), carried out under the direction of Associate Professor Hideaki Ohba, University Museum, University of Tokyo, to whom I am deeply indebted. Thanks are due to Professor Kunio Iwatsuki, University of Tokyo, for his encouragement. I am also grateful to the late Dr. Hiroshi Hara (then Professor Emeritus of the University of Tokyo) for his valuable suggestions and encouragement. I would like to thank Mr. Gen Murata, Kyoto University, for his valuable comments. Dr. Mitsuo Suzuki, Kanazawa University, Dr. Nobuhira Kurosaki, Shoei Junior College, Mr. Kenji Midorikawa, Tokyo, Mr. Sadao Tsutsui, Fukuoka, Mr. Toshio Sakata, Kagoshima, Mr. Hideo Nagase, Gifu, Mr. Nobuo Futamura, Gifu, and Mr. Noboru Kuramoto, Tokyo, were kind enough to supply many valuable materials for this study or accompany me on field surveys. Comments and constructive criticism were offered by the members of the University Museum and the Botanical Gardens, University of Tokyo.

I also express my appreciation to the curators of the following herbaria: A, CAL, GH, HK, K, KAG, KANA, KIEL, KYO, L, LE, MAK, NA, SAP, SHO, TI, TNS, TOFO, and TUSG, For permitting me to survey herbarium specimens and to borrow valuable collections.