THE MORPHOLOGY AND AFFINITIES OF GNETUM 1 7/ 
on the ancestry of the Angiosperms is the Mesozoic Bennetitales. 
Their claims have been advocated by Arber and Parkin (i) and by 
Scott (24). According to the latter author they are three in number: 
(i) the organization of strobili on the same plan as in typical Angio- 
sperm flowers (2) the formation of a fruit enclosing the seeds (3) the 
exalbuminous nature of the seeds. It is admitted that these are the 
only points whether of phylogenetic significance or not in which the 
Bennetitales resemble Angiosperms. In regard to the exalbuminous 
nature of the seeds it need only be remarked that by no means all 
Angiosperms have such seeds and certainly this is not the case in 
many primitive forms. In regard to the formation of fruit enclosing 
the seeds the claims of Gnetum are even stronger for the fruit of the 
latter is formed in a much more typically Angiospermic fashion. 
The organization of the strobili while resembling that of an Angio- 
sperm flower in regard to the arrangement of the mega- and micro- 
sporangia is widely different in many important respects: The 
ovules are stalked; there is nothing resembling a carpel (a most im- 
portant point); there are sterile scales between the ovules; the mic- 
rosporophylls with their fern-like branching and numerous sporangia 
are as different as possible from the Angiosperm stamen. Moreover 
if we conclude that the Angiosperm flower of the Magnolia type has 
been derived from the Bennetitales strobilus we encounter the insur- 
mountable difficulty of explaining the occurrence of the simple catkin- 
like inflorescence on forms admittedly primitive. On the other hand 
these catkin-like inflorescences relate themselves strikingly to the 
strobili of Gnetum. 
Apart from the organization of the strobili there are many points 
which seem to preclude the possibility of the Bennetitalean ancestry 
of the Angiosperms. Some of them are: the Cycadean habit and 
leaves, all the essential anatomical points (see Thompson, 27), un- 
doubted possession of motile spermatozoa, primitive Gymnosperm 
condition and absence of anything foreshadowing the Angiosperm 
condition in gametophytes, endosperm or embryo. Now in all these 
respects, as has been shown, Gnetum approaches the Angiosperm 
conditions and in many of them has actually reached those conditions. 
As between the Bennetitales and Gnetales, therefore, the decision 
must surely be made in favor of the latter group. Nor is it sufficient 
to assume with Arber and Parkin (2) that the Gnetales and Angio- 
sperms developed in parallel lines from the Bennetitales. Aside 
