FERTILIZATION IN LILIUM 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 243 
WANDA WENIGER 
(WITH PLATES XI-XIII) 
Introduction 
The cytological phenomena of fertilization have been studied 
with greater detail in the gymnosperms than in the angiosperms. 
This paper is the result of an attempt to discover whether there 
is a similarity between the process of fertilization as already 
described for gymnosperms and that of angiosperms. Lilium has 
long been the type used in the study of fertilization in the class- 
room; it was chosen for the subject of study in this case because it 
lends itself particularly well to cytological work. The writer is 
indebted’ to Dr. C. J. CHamBERLAIN for the suggestion of the 
problem and for his helpful assistance throughout the progress 
of the work. 
In Pinus (1, 3, 5, 7, 8), Tsuga (14), Juniperus (18, 19), and 
A bies (12) evidence has been brought to bear upon the fact that no 
fusion of the male and female chromatic substance takes place. 
BLACKMAN (1), in 1898, described the cytological features of 
fertilization in Pinus silvestris. While the outlines of the 2 sexual 
nuclei are still visible, the chromosomes are found in 2 separate 
clumps; and even on the spindle fibers of the first division they 
can be distinguished into 2 groups. After a longitudinal splitting 
the half chromosomes fuse together in the telophase of the division. 
CHAMBERLAIN’S (3) account of oogenesis in Pinus Laricio 
includes figures of the male and egg nuclei. He states that after 
the male pronucleus is within the.oosphere nucleus the chromatin 
of the 2 pronuclei appears as 2 distinct masses in the spireme stage. 
“Perhaps segmentation of the 2 spiremes occurs while they are still 
separate.’ In Tsuga canadensis MuRRILL (14) reports 2 sets of 
chromosomes distinct in the equatorial region of the first spindle. 
259] [Botanical Gazette, vol. 66 
