THE MORPHOLOGY AND AFFINITIES OF GNETUM I7I 
observed a considerable mass of endosperm before fertilization oc- 
curred. 
2. In typical Gymnosperms there is nothing which resembles 
the fusion of nuclei which in Angiosperms precedes endosperm de- 
velopment. In typical Angiosperms two nuclei only of the female 
gametophyte, a micropylar and an antipodal, unite. In Gnetum 
several nuclei in each compartment unite. The chief differences 
from Angiosperms are (i) that many fusion nuclei result and (2) 
that several nuclei unite to form a single fusion nucleus. Nevertheless 
the essential fact remains that a fusion of nuclei occurs before the 
endosperm develops. And it should be remembered that in several 
primitive Angiosperms more than two nuclei unite. Thus in Pep- 
eromia hispidula Johnston (11) reports that 14 nuclei fuse to form 
the endosperm nucleus. Therefore one of the two differences between 
Gnetum and Angiosperms in this connection disappears (and it is 
significant that of all the Angiosperms, forms like Peperomia should 
most resemble Gnetum). The other difference, the number of fusion 
nuclei, loses its importance when we remember that in G. gnemon, 
there is a tendency to reduce the number [see (3) below]. Accordingly 
it seems a reasonable conclusion that the fusion of nuclei in Gnetum 
is really a forerunner of that in Angiosperms. 
3. In Gymnosperms the whole female gametophyte is endosperm 
tissue. In Angiosperms endosperm formation involves only two 
nuclei of the female gametophyte. G. sp. jj resembles the Gymno- 
sperms in that all the gametophytic nuclei contribute to endosperm 
formation. There are many fusion nuclei throughout the sac. But 
in G. gnemon only the nuclei at the bottom of the sac are concerned 
in endosperm formation. At most ten compartments with their 
fusion nuclei participate while all the rest of the sac (by far the larger 
part) has nothing to do with it. Within the genus itself, therefore, 
there is a marked tendency away from the Gymnospermic condition 
in G. sp. jj toward the more Angiosperm-like condition of G. gnemon. 
The only other important difference between the endosperm of 
Angiosperms and that of Gymnosperms is one of which we find no 
trace in Gnetum, namely, the fertilization of a fusion nucleus by a 
male nucleus. No male nucleus is concerned with endosperm for- 
mation in any species of Gnetum. At this important point, there- 
fore, the resemblance between Gnetum and the Angiosperms breaks 
down. In other words Gnetum does not throw much light on the 
