AMERICAN 
JOURNAL OF BOTANY 
Vol. Ill April, 1916 No. 4 
THE MORPHOLOGY AND AFFINITIES OF GNETUM 
Walter P. Thompson 
I. Introduction 
The Gnetales have been called the lure and the despair of the 
morphologist. They are alluring because they promise to give a 
solution to the morphologist's great problem, the origin of the Angio- 
sperms. They are a despair in that heretofore, in spite of many 
efforts, no one has been able either to establish convincingly or to 
disprove their Angiospermic connection. Some botanists maintain 
that they occupy a sort of intermediate position between Angiosperms 
and Gymnosperms; others believe that they represent a line of evolu- 
tion which developed parallel to the Angiospermic line from the same 
ancestral group; others again deny all relationship between the two 
groups, believing that the undoubted points of resemblance have 
been independently acquired. Nor is there agreement in regard to 
their Gymnospermic connection. While most morphologists are 
agreed that they are the highest of the Gymnosperms some believe 
that they have been derived from the Bennetitales and others that 
they have come from the Coniferales. 
An obvious contribution toward a solution of these problems 
would be a thorough investigation of the essential morphology of 
the genus Gnetum about which our information is very meager. In 
addition to its own interest and its bearing on general problems of 
Gnetalean and Angiospermic affinities, it should throw light on other 
problems such as the morphology of the gametophytic structures 
and endosperm of Angiosperms. Undoubtedly the morphology of 
Gnetum would have been thoroughly investigated long ago but for 
the great difficulty in securing proper material. With our present 
accumulation of knowledge in respect to the gametophytic conditions 
and endosperm of almost every other living genus of Gymnosperms 
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