PREFACE. 
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THE “ Flora of Tropical Africa” has met with many vicissitudes. It 
was projected by Sir William Jackson Hooker as part of the series of 
Colonial and Indian Floras to be produced at Kew which he initiated. 
The immediate impulse which led the Government to sanction the 
undertaking was given by Dr. Livingstone on his return from the 
Zambesi Expedition (1858-64), to which Dr. (afterwards Sir John) Kirk 
had been attached as naturalist. The work having been offered to Dr. 
Kirk and declined by him was entrusted in 1864 to Sir Joseph Hooker 
and Professor Oliver jointly, and was to be completed in four volumes, 
Sir Joseph Hooker succeeded to the Directorship of the Royal 
Gardens in 1865, and was in consequence obliged to resign the prepara- 
tion of the Flora to Professor Oliver, although he contributed some share 
to both volumes 1. and 11. Professor Oliver further obtained the assist- 
ance of other botanists. 
Vol. 1. appeared in 1868, vol. o in 1871, and vol. Im. in 1877. 
It was soon evident that the work would exceed the limits at first 
assigned to it. Not less than five additional volumes will be now 
required to enumerate completely and describe the known plants of 
Tropical Africa. 
In the preface to the first volume Professor Oliver states that for 
the geographical region to which he gave the name Lower Guinea he 
was almost wholly dependent on the Angolan collections made at the 
cost of the Portuguese Government in 1853-61 by Dr. Frederick 
Welwitsch. 
This botanist, Professor Oliver adds, “‘ has freely granted us the 
opportunity of inspecting his collections, which, in respect of judicious 
selection and admirable preservation, are without rival. His carefully 
accurate notes upon the fresh plants have also been at our service. 
Without the access to Dr. Welwitsch’s Herbarium this region would 
have been comparatively a blank in the present work.” 
Dr. Welwitsch died in 1872, having bequeathed his Herbarium to 
the British Museum. This led to prolonged litigation on the part ot 
the Portuguese Government, ending in a compromise. But the 
