PRELIMINARY NOTE ON THE MORPHOLOGY OF GNETUM 
W. p. Thompson 
The writer has collected and examined abundant embryological 
material of several species of Gnetum in the hope of securing informa- 
tion concerning the affinities of the Gnetales, and of throwing light on 
the origin of the gametophytic conditions and endosperm of the 
Angiosperms. Some of the results of the study are enumerated 
below. The detailed information will be published shortly. 
1. The pollen grains sometimes germinate well up in the so-called 
"vStyle," the pollen tubes then growing down to the nucellus as in 
the Angiosperms. Usually, however, germination takes place on the 
tip of the nucellus. 
2. In the male garnetophyte no prothallial cells are produced. 
Distinct male cells are formed. 
3. Only free nuclei (never cells) are formed in the embryo-sac 
before the pollen tube enters, though cells are formed before fertiliza- 
tion takes place. 
4. One or more eggs are definitely organized just before the pollen 
tube enters, usually while it is pressed against the side of the sac. 
5. Before fertilization takes place the female gametophyte becomes 
divided into a large number of multinucleate compartments. All the 
nuclei in each compartment then unite to form a fusion nucleus. 
Fertilization is delayed until the fusion nuclei are formed. 
6. The endosperm is formed by the divisions of the fusion nuclei 
in the lowermost compartments. 
7. Coenocytic pro-embryonal tubes are formed which grow down 
into the endosperm and branch freely. 
The bearing of conclusions five and six on the morphology of the 
endosperm of Angiosperms is obvious. The whole study indicates a 
close relationship between Gnetum and the Angiosperms. 
University of Saskatchewan. 
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