Pinus silvestris . 
33 
The first division of the fertilized oosphere was several 
times observed, but, owing to the paucity of chromatin and 
consequent difficulty of staining, I only once succeeded in 
counting the chromosomes with certainty, and I found, just 
as we would expect from comparison with the Angiosperms, 
1 6 chromosomes (Fig. 26). This nuclear plate was formed 
in the middle of the archegonium in an oblique position. 
Subsequent divisions, which took place at the base of the 
archegonium, were also observed (Fig. 27). These were 
characterized by very pronounced striae radiating from the 
poles into the protoplasm of the oosphere. Fig. 28 represents 
a peculiar structure which was found in the protoplasm of the 
oosphere before fertilization, exactly resembling the nuclear 
spindle in karyokinesis, without having a trace of chromatin 
evident. In several cases the achromatic threads show 
a greater refractiveness about the middle of their length, 
exactly resembling the beginning of a cell-plate. The pollen- 
tube had only reached the top of the neck of the archegonium 
in the specimen from which these are figured. 
Having seen that the nuclei of the nucellus had 1 6 chromo- 
somes in the cases counted, while those of the integument 
had also sometimes 24, it seemed interesting to ascertain the 
number of the chromosomes in the nuclei of the primary 
meristem of the growing-point. Unfortunately I had no 
suitable material of Pinus silvestris , and had to use instead 
Pinus Laricio and Picea orientalis . In these two plants the 
nuclei of the primary meristem contained 16 chromosomes in 
each case where these could be counted. In sections below 
the apex the number was 16 in the cambium and 24 in the 
young cortex. Sufficient cases, however, were not examined 
to render it certain that this is a general rule. 
I wish, in conclusion, to express my gratitude to Prof. 
Strasburger for his great kindness to me during my work in 
his laboratory, and to Dr. F. Noll for his assistance to me on 
many occasions. 
D 
