PREFACE 7 



in the phraseology indicates a difference in the structure of 

 the wood concerned. 



For the formal matter, vernacular names, localities, etc., we 

 are indebted to the authors enumerated in the Bibliography, 

 to whom we express our thanks. Special mention should be 

 made of Mr. Harold Unwin's compendious work on Forests 

 and Forestry in Nigeria, and to Mr. J. H. Holland's The Useful 

 Plants of Nigeria, for not only have we availed ourselves of 

 the great amount of information therein accumulated by these 

 authors themselves, but in some cases we have been led to 

 seek the works of other authors by means of their references 

 and bibliographies, for which they should have credit. 



The whole of the specimens described herein, as well as 

 many others from various sources, are deposited in the collec- 

 tion of the School of Forestry, Cambridge, where they may be 

 consulted. To facilitate this we have quoted the serial number 

 of each specimen. 



Unfortunately, it is but rarely that a specimen has been 

 accompanied by the name of the collector. As this detail is 

 of the first importance we strongly impress upon all friends 

 who send us specimens the imperative necessity of proper 

 authenticity. Failing this, our custom is to accept a specimen 

 as being of a reputed species whenever we find that it agrees 

 with others similarly reputed, that have been received from 

 different sources, otherwise the identity of the specimen must 

 be regarded as provisional only. 



The generic numbers given are those of Bentham and Hooker 

 (see also Th. Durand's Index Plantarum Phanerogamorum), the 

 sequence corresponding to the systematic arrangement of those 

 authors. Though the classification of Engler is more in vogue, 

 we adhere to that of Bentham and Hooker, inasmuch as most 

 of the literature with which we have to do is based on the 

 latter system, and also because the extensive collection of the 

 School of Forestry is arranged according to the same plan. 



The notes supplied to us by the Conservator of Forests have 

 been appended to the various species concerned. 



Much help has been received from the members of the 

 Cambridge University Forestry Association, especially from 

 Mr. A. J. Wilson, by whom most of the photographs for our 

 plates have been taken. 



