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ON SOME STAGES IN THE LIFE HISTOEY OF GINETUM * 
By H. H. W. Pearson, Sc.D., F.E.S., and Mart E. H. Thomson, B.A. 
(With Plates XLY-L.) 
Since the time of Grriffith,t the life history of G-netum has been studied 
by many botanists, each of whom has done something to advance the know- 
ledge of this remarkable genus, which, nevertheless, is still very incomplete. 
Material for the study is difficult to obtain, and when obtained is usually 
more or less disappointing in the results which it yields. + 
The present investigation resembles those that have preceded it in 
respect of its incompleteness. It carries the story a little farther, but it 
leaves considerable gaps to be filled by future work. It has extended over 
a period of seven years, in the course of which material from West Africa, § 
Poona, Darjeeling, Ceylon, Penang, Singapore, and Buitenzorg, representing 
G. africanum, G. Bucliholzianum, G. Gnemon, G. scandens, and two species 
of doubtful identity have been studied. Thousands of sections have been 
examined |1 and some results have been published.^ This paper contains 
probably the last contribution to the life history which this material will 
furnish. 
Our failure to elucidate certain stages in the life history, in spite of this 
large supply of material carefully collected and fixed by those who have 
been so good as to assist us, is due to causes which themselves suggest 
some interesting conclusions regarding the biology of some species of 
Gnetum. We find no indication of specific disease such as Lotsy describes 
* Percy Sladen Memorial Expeditions in S.W. Africa, No. 78 ^art). 
t Griffith, 1859. 
X Cf. Lotsy, 1899, 1903. 
§ As previously stated (Pearson, 1912, 1915 A & B), we owe this material to 
the kindness of the Director of the Buitenzorg Grardens, Major Gage, Mr. I. H. 
BurkiU, Prof. Gammie, Mr. W. Talbot, the late Dr. R. H. Lock, Mr. C. C. Calder, 
Mr. G. H. Cave, Mr. J. Gossweiler, Herr G. Zenker, and the Percy Sladen Memorial 
Expedition in S.W. Africa, 1908-1909. 
II We are indebted to Miss F. Goldmann, B.A., for some assistance in preparing 
sections. 
% Pearson, 1912, 1915 a, 1915 b ; Caporn, 1916 ; Thomson, 1916. 
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