CONIFERALES 



337 



fertilization is Hutchinson's'" account of Abies halsamea. He 

 found the separate spiremes of the two gametes and their segmenta- 

 tion forming two groups of chromosomes, each with the x number. 





^:^'<i-.. 



^ 







St# 





£ 



^,:^^ 



/Ji4, 







D 





Fig. 327.— Fertilization in Pinus: A, Pinus sylvestris, sperm nucleus much smaller 

 than the egg nucleus; June 19; X 13s; after Blackman;s6 B, P. laricio, nuclei of egg and 

 sperm in spireme stage; X 500; after Chamberlain ;'«4 C-F, P. strobus, later stages than 

 B, all showing that there has been no fusion of chromatin; X31S; after Dr. Margaret 

 Ferguson."'^ 



