1 94 Ferguson. — Development of the Pollen-tube and the 
the Gymnosperms, and rendered it highly desirable that 
fertilization and associated phenomena should be worked 
out for other members of this group by the more modern 
methods of investigation. 
The present studies were undertaken in the fall of 1897. 
They have been carried on in the botanical laboratory of 
Cornell University under the direction of Professor George 
F. Atkinson. Professor Atkinson’s interest in the work has 
been a constant inspiration to me, and his counsel invaluable. 
I also take pleasure in acknowledging my appreciation of the 
valuable assistance rendered by Dr. E. J. Durand. 
Methods. 
On November 15, 1897, and each week thereafter until 
December 35, cones of Pinus Strobus , P. austriaca , P. rigid a, 
and P. montana , var. uncinata , were collected, and ovules pre- 
served. Material was fixed occasionally during the remainder 
of the winter. Beginning with April 1, the species named 
above and also Pinus resinosa were collected once each week. 
Collections were made twice each week during the month of 
May and three times a week for June. From June 10-30, 
a period which was sure to cover fertilization, cones of Pinus 
Strobus were collected every day at about nine o’clock in the 
morning, and frequently again at four in the afternoon. 
During May and June the little young cones were collected 
for each species as well as the more mature cones of the 
previous year’s growth. After July 1, the older cones were 
no longer collected, but the young cones of Pinus Strobus , 
P. austriaca , and P. rigida were collected once each week until 
November 15. Cones of Pinus Strobus were again collected 
regularly, as described above, during the spring and early 
summer of 1899. 
Each time of collecting, ovules were put up from several 
cones of each species, and these cones were not taken from 
the tip of one branch, but from different branches. Ovules 
were fixed from the central portion only of the cones. In 
the first stages of development the cones were fixed entire 
