The purpose of this work is to summarize our present
knowledge of the Acereous plants of Chinai, Since Pax
published his last monograph of Aceraceae2 in 1902, the
multiplicity of new species and the huge collections of
material which are not easily identified, have particularly emphasized the somewhat pressing requirement for a critical review and the necessity for supplementary descriptions and special notes.This work was continued over a period of more than
five years. During this time various herbaria were
visited where type- specimens and numerous collections
were carefully examined. The main work has been done
at the Royal Botanic Garden, Edinburgh. I am greatly
indebted to Professor Sir William Wright Smith, who
has given me continual encouragement during the course
of my work. My best thanks are also due to Dr. J. M.
Cowan for invaluable suggestions and criticism; to Mr.
W. E. Evans for special arrangement of material; to Cdr.
J. T. Johnstone for assistance in gathering literature,
and to Dr, H. R. Fletcher for his critical reading of
some parts of the manuscript. I should like also to
tender my sincere thanks to Professor S. S. Chien of the
Biological Laboratory of the Science Society of China,
Nanking, under whose supervision I laid the basis of my
work there. I am very obliged to Professor A. Rehder of the Arnold Arboretum, Jamaica Plain, Massachussetts,
U.S.A.; Professor H. Handel -Mazzetti of the Botanic
Institute and Garden, Vienna, Austria; Professor H.
H. Hu of the Fan Memorial Institute of Biology, Peiping;
Professor W. Y. Chun of the Botanic Institute of Sun - Yatsen University, Canton; and to Professor F. P.
Metcalf of the Lingnan University, Canton, for their
kindness in sending me material, and valuable suggestions
on some special problems. My warmest thanks are also
due to the authorities of various herbaria - too numerous
to be mentioned individually - who sent specimens on
loan. I wish to express my special acknowledgment to
Mr. J. Ramsbottom of the Department of Botany, British
Museum (Natural History, London; to Sir Arthur W. Hill
and Dr. A. D. Cotton of the Royal Botanic Gardens, Kew,
England; to Professor L. Diels and Professor R. Pilger
of the Botanic Museum, Berlin -Dahlem, Germany; to
Professor F. Pax and Professor H. Winkler of the Botanic
Institute, Breslau, Germany; to Professor K. Sussenguth
of the Botanic Garden, Munich, Germany; to Dr. K. Keissler
of the Natural History Museum, Vienna, Austria; to
Professor F. Knoll of the Botanic Institute and Garden,
Vienna, Austria; to Professor G. Negri and Professor A.
Messeri of the Botanic Museum, Florence, Italy; and to
Professor H. Humbert of the Natural History Museum,
Paris, France, for their courtesy in granting me the privilege of examining specimens in their herbari
