IV 
PREFACE. 
To Dr. Hooker, C.B., E.D.S., I owe many thanks for aid and 
facilities rendered me in this and other researches for a long period, 
and to Professor Oliver, E.D.S., J. G. Baker, E.L.S., and J. D. Jack- 
son, A.L.S., Esqrs., my best thanks are due for assistance and 
facilities in consulting the Herbarium and Museum. 
To my late dear friend Dr. Eriedrick Welwitsck I am indebted for 
matter relating to Africa, and but for his death this Deport would 
have been graced with a promised monograph on the Landolphias. 
To Dr. Diehard Spruce’s kindness I am indebted for the most 
valuable information relating to the Heveas, and to my numerous 
correspondents at home and abroad I tender my warmest thanks 
for their invariable kindness in replying to my queries and requests. 
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