Overton—On the Boot Tips of Podophyllum Peltatum. 311 
Blackman (’98), Chamberlain (’99), and especially Miss Fer¬ 
guson (’04) have shown that in Pinus the parental elements re¬ 
main distinct during fertilization, observing that during the first 
division of the fertilized egg the parental chromatin elements form 
two separate spirems. The independent formation of maternal 
and paternal chromosomes has also been described in Tsuga by 
Murrill (’00), in Juniperus by Noren (’07), and in Abies by 
Hutchinson (‘15), the later of whom describes the maternal and 
paternal chromosomes as being formed independently as in most 
conifers, but becoming paired side by side and twisting about 
each other. The number of paired chromosomes is haploid, each 
pair of which, Hutchinson holds, segments transversely to form 
the diploid number. Chamberlain (’16) finds a similar pairing 
of the chromosomes in Stangeria at fertilization. In the angio- 
sperms few detailed accounts of the behavior of the chromosomes 
during fertilization and the first division of the egg are at hand, 
except that of Sax (’18) on Fritillaria and Triticum in which he 
holds that there is no indication that the chromosomes of the male 
and female gametes are in separate groups, or that they pair in 
the first division of the zygote. It is apparent that the pairing of 
the chromosomes may take place at the time of fertilization, as 
Hutchinson and Chamberlain have described, or later as indi¬ 
cated by the results of Blackman, Chamberlain, and Ferguson on 
Pinus and by those of other workers on other conifers. From my 
own studies upon the vegetative nuclei of plants showing pro¬ 
chromosomes I believe that the parental elements remain distinct, 
but I am convinneed that there is no permanent spatial separation 
of the parental chromosomes as described for the first division of 
the egg of Pinus. Miss Nothnagel (’18) reports for Lilium mar- 
tag on and Trillium grandifolium the presence in the fertilized egg 
of two distinct and separate spirems arising from the parental 
chromatin elements, and two separate and distinct groups of chro¬ 
mosomes, which she regards as evidence that the chromosomes 
maintain their individuality from one generation to the next. 
Miss Weniger (’18) also finds that in Lilium there is no fusion 
of the parental chromatic elements in the fertilized egg and that 
each parental spirem segments into the chromosomes which come 
together in pairs, in the manner described by Hutchinson, on the 
equatorial plate. I am further convinced from my studies on 
plants showing prochromosomes as well as from my present 
