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H. H. W. PEARSON, F.R.S., Sc.D. 
of the embryo-sac each “cell” has 1 — 2 nuclei and later as many as 5, while 
in the lower part of the sac each “cell” has 2 — 12 nuclei. The “cells” with 
2 — 5 nuclei in the micropylar region of the embryo-sac produce embryo-sac 
tubes which grow up towards the descending pollen-tubes. On March 3, 
1908, he discussed the question of nomenclature with regard to the “endo- 
sperm.” “In Gnetum and Welwitschia the embryo-sac becomes filled with 
nuclei all of which are probably capable of being fertilised, i.e. all are potential 
gametes. Of these a few are functional. The remainder, or most of them, 
fuse in groups of 7, 8, 9, 10 or more and form a number of fusion-nuclei which 
I believe to be homologous with the definitive nucleus of the Angiosperm. 
These fusion-nuclei on division give rise to a tissue whose later growth is 
considerable and is so highly organised that the tissue (endosperm) must be 
regarded as an organism. This organism is no.t in the direct line of the 
life-cycle and belongs neither to the sporophyte nor to the gametophyte. 
Now as the term endosperm is physiological (according to its author’s 
definition) and applies equally to the prothallus of Pines and to this endosperm 
of Welwitschia and the Angiosperm I want a morphological name for my new 
organism. I propose to call it the Trophophyte.” 
The Welwitschia work naturally led to an attack on Gnetum and one of 
the main objects of the Expedition of 1908 — 09 was to obtain material of 
Gnetum africanum from Angola. The first part of this journey was made in 
company with the Magnetic Sixrvey Expedition of the Carnegie Institute 
under the leadership of his close friend and colleague Dr J. C. Beattie. On 
April 12, 1910, he wrote: “I have both Gnetum africanum and G. scandens 
on the go and I have cut about 10 ovules of each.... While I am not yet able 
to prove it to the satisfaction of a sceptic I have myself no doubt that the 
endosperm [Gnetum] is formed as in Welwitschia (the attitude is I am afraid 
unscientific but it is I think impossible to keep one’s mind open until the proof 
is complete).” In November, 1915, he added: “I have at last settled the 
question of the resemblance of the endosperm [of Gnetum] to that of Wel- 
witschia; it is formed in exactly the same way, which pleases me mightily.” 
Prof. Pearson consented to contribute a volume on the Gnetales to the 
‘Cambridge Handbooks’ edited by Mr Tansley and myself and this work 
may, we hope, be far enough advanced to be published. In a letter dated 
April 20, 1916, he wrote: “A large part of the book on the Gnetales is 
written though it will need some revision.... As to the Gnetalean- Angiosperm 
alliance, there must be one I think, but at present I cannot bring myself to 
believe that it is direct. If they are not connected that endosperm wants 
a lot of explaining. The trouble is that I cannot yet make head or tail of the 
flower, and the relation between Ephedra and the others is extremely puzzling. 
The latter is probably very simple if we only had the key— the former I dream 
about, so far unsuccessfully. As to Bennettites I think I made far too much 
