604 Pearson . — On the Micro sporangium and Micro spore of 
Among the objects of the Percy Sladen Memorial Expedition of 1908-9 
was that of obtaining material for the study of the life-history of 
G. africanum. This species was collected at Montobello in the Cazengo 
district of Angola, by Mr. J. Gossweiler, F.L.S. and the writer, in April, 
1909. The ovules then obtained have yielded information regarding the 
condition of the embryo-sac and its contents both before and after 
fertilization, but they have not made it possible to describe completely the 
origin and development of the endosperm. It is hoped that, by the kind- 
ness of Mr. Gossweiler, a further supply of ovular material will be available 
in the course of a few months. Meanwhile, the following facts established 
for the male inflorescence and flower are placed on record. 
As far as was possible with the information then available, the visit to 
Central Angola was timed to coincide with the later stages of ovular 
development, and it was hardly expected that young male inflorescences 
would be seen. While ovules were obtained in abundance only four male 
spikes were found ; these have yielded all the stages shown in Pis. LX, LXI, 
Figs. 5-20. A further supply was gathered in the same locality by Mr. 
Gossweiler in January, 1910 ; these were preserved in alcohol and have been 
used in the investigation of the grosser morphological characters now to be 
described. Herr G. Zenker has most kindly sent me material of the male in- 
florescences of G. Buchholzianum from the Kameruns. A comparison of the 
internal morphology of these with that of G. africanum has led to very inter- 
esting conclusions regarding the degree of affinity between the African species 
and the important differences which separate them from the Indo-Malayan 
forms which have been studied. I am further greatly indebted to 
Mr. I. H. Burkill, Professor Gammie, and Mr. W. Talbot, C.M.G., for 
supplies of material of G. scandens. 
The structure of the male inflorescence and the development of the 
parts of the flower of various species of Gnetum have been described by 
Griffith, Strasburger, Karsten, and Lotsy. Their results are scattered and 
some of them are in danger of being overlooked ; it may therefore serve 
a useful purpose to summarize them briefly. 
Griffith 1 describes the inflorescence in a few species. In G. Bruno - 
nianum he notes the presence of two sterile bracts on the peduncle. 
The bracts subtending the flowers are connate at the base and form an 
obsolete involucral ring ; in its axil are a single ring of female flowers and 
many male flowers developing basipetally (‘ pluriseriatis, superioribus primo 
evolutis ’). The female flower consists of a central fleshy ovate body which 
‘ appears to be a naked ovule ’. ‘ The nature and structure of the two 
envelopes indicate them to be perianthial.’ Articulate hairs occur between 
the flowers. In a climbing species whose specific name is not given, he 
observes the presence of two vascular bundles in the axis of the male flower : 
1 Griffith (’54). 
