436 BOTANICAL GAZETTE [ DECEMBER 
and of oogenesis, the phenomena of fertilization, and the early segmentations 
in P. Strobus. In the main, there is abundant confirmation of the more 
oe aaa work of previous investigators. Besides, the genus has been 
found variable enough to make the full study of any species valuable. Some 
of the points to be noted are as follows: The “ antheridial”’ (generative) cell 
is said to divide ‘before the beginning of winter,” which indicates a wide 
range of time in the genus for this event. A definite order of precedence for 
the stalk and “ generative’ (body) cells in the pollen tube is given, the 
former being said to pass the latter and consort with the “ vegetative ” (tube) 
nucleus. The body cell is said to be peculiar in never being limited by a 
cell wall, and a survival of the centrosome is suggested in the division of its 
nucleus. The interesting claim is made that “sperm cells are never formed, 
but the sperm nuclei remain surrounded by a common mass of cytoplasm,” 
and become unequal very early in their history. In some cases, after fertiliza- 
tion, the tube and smaller sperm nuclei were observed to divide amitotically. 
The most interesting fact in connection with fertilization and segmentation is 
that in addition to'the well-known fact that there is no real fusion of the 
sexual nuclei in fertilization, the author has been able to observe that “the 
two chromatic groups remain distinct until the nuclear plate stage”’ of the 
first segmentation. No centrosomes are claimed for the first segmentation, 
‘but the entire activity connected with this mitosis indicates that the sperm 
nucleus, under the influence of the egg cytoplasm, is the agent which initi- 
ates and controls the division.” The frequently noted similarity between the 
fertilization processes in the gymnosperms and animals is presented in con- 
siderable detail. These papers are valuable additions to our rapidly increas- 
ing literature of gymnosperms.—J. M. C. 
ES ae 
