of Fertilization in A ngiosperms . 709 
resemblance to a true act of fertilization must then be con¬ 
sidered as accidental. 
Strasburger (11, p. 308) has expressed this view with great 
force. It appears to him inevitable that the presence of the 
male element in the original nuclear fusion should affect the 
character of the tissue derived from it, as shown by de Vries 
and Correns, but he does not regard this as a proof of true 
‘ generative fertilization/ or in other words of amphimixis. 
On the contrary, he proposes to classify the triple fusion among 
the phenomena of ‘vegetative fertilization/ or, as I have 
hitherto called it, growth-stimulus. 
It is clear that this proposal is based on a double assump¬ 
tion. In the first place, Strasburger considers that the endo¬ 
sperm is phylogenetically a prothallus, and that the nuclear 
fusion which gives rise to it has never been a true act of 
fertilization, or to use his own term a ‘ generative fertiliza¬ 
tion.’ In the second place he believes that there is no 
purpose in the transference of paternal characters to the 
endosperm. Even if it should be proved, later that such trans¬ 
ference originally began at a time when the endosperm was 
clearly a second embryo, and the conjugation giving rise to it 
a normal act of fertilization, he believes that the process has 
now degenerated so far that it is physiologically a mere 
stimulus to growth ( 1 . c., p. 308). On this view the presence 
of paternal characters in the endosperm is either an accident 
inseparable from the mode of stimulus which provokes its 
formation, or a mere survival with no physiological meaning 
at the present time. 
We must wait for the solution of the historical question. 
But no one, so far as I am aware, has as yet suggested that 
the transference of paternal characters to the endosperm may 
still be of advantage to the plant. This suggestion—which 
seems to me of great importance—I owe to Miss Thomas, who 
has herself demonstrated the existence of ‘ double fertilization 5 
in Caltha palustris , (Thomas, 12 , 13 ). I am indebted to her 
for permission to publish her hypothesis here for the first 
time. 
