The Origin of Triple Fusion. 285 
An endosperm having an origin such as that outlined above, 
would be of pro-embryonal nature, but derived from cells which 
had already, earlier in their phylogenetic history, assumed a 
nutritive function. Thus two views very generally held with regard 
to the endosperm of Angiosperms, first that, being a nutritive tissue, 
it must be prothallial, second that, being a product of fertilization, 
it must be an embryo, would be hereby reconciled. Moreover the 
suggestion made by Miss Sargant (8) (to whom I owe much kind and 
suggestive help), that the endosperm is to a certain degree a 
monstrous embryo, owing to some want of balance in the consti¬ 
tution of its nuclei due to its threefold parentage, is in no way 
precluded. 
Further careful investigation of the Gnetaceae is needed to 
give this theory a sure foundation in fact ; unfortunately the 
readiness with which these ovules fall a prey to insect attacks is a 
serious obstacle to their study. Only when the fate of the second 
male nucleus has been determined with certainty in forms which 
are more or less closely related to the ancestors of the Angiosperms, 
as these seem to be, will a final solution of the problem be possible. 
LITERATURE. 
1. Land, W. J. G. “ Fertilization and Embryogcny in Ephedra trip urea." 
Bot. Gaz., Vol. XL1V., 1907. 
2. Berridge, E. M., and Sanday, E. “Oogenesis and Embryogenv in 
Ephedra distacliya." New Phytologist : 6: 
pp. 128—134, 167—174: 1907. 
3. Porsch, O. “ Versuch einer phylogenetischen Erklarung des 
Embryosackes, und der doppelten Befruchtung 
der Angiospermen. Dresden, 1907. 
4. Hartog, M. “ Some Problems of Reproduction”: A Comparative 
Study of Gametogeny and Protoplasmic Senes¬ 
cence and Rejuvenescence. Quart. Journal, 
Microsc. Sci., Vol. XI., 1891. 
5. Thomas, E. N. “ Some Aspects of Double Fertilization in Plants.” 
Science Progress: 3: 1907. 
6. Land, W. J. G. “ A Morphological Study of Thuja." Bot. Gaz., 34, 
1902. 
7. Lotsy, J. “Contributions to the Life History of the Genus 
Gnetum. Ann. du Jar. Bot. de Buitenzorg. 
Tom. XVI., 1899. 
8. Sargant, E. “ Recent Work on the Results of Fertilization in 
Angiosperms ” Ann. of Bot., XIV., December, 
1900. 
