vi PREFACE, 
describe as comprehensively as possible the important caoutchouc- 
containing and medicinal plants which the order includes in Tropical 
Africa. 
1 must again record my acknowledgments of the assistance given 
me by Mr. C. H. Wright in preparing the manuscript for the press and 
in checking the proofs, and to Mr. N. E. Brown for working out the 
geographical distribution. 
For the detailed topography the third edition of the ‘ Spezial- 
Karte von Afrika,” Gotha: Julius Perthes, 1893, has been chiefly 
used, 
We. ee: 
Kew, February 1902. 
