122 BOTANICAL GAZETTE [AUGUST 
not generally so; and when it does occur it may be considered 
as a failure to secure the results aimed at. When several pollen 
tubes have reached the archegonial group (as many as five have 
been noticed) the entrance of two or more sperm cells into an 
archegonium is not unusual, but when the number of tubes is 
only one or two it less often occurs. Pollen tubes sometimes are 
so abundant that all cannot pass into the depression above the 
archegonial group. Some then remain in different positions 
around the tip of the prothallium, and are often to be seen 
unchanged after their more fortunate neighbors have fertilized 
the archegonia. The central cell of such pollen tubes often 
divides at the same time with those over the archegonia, but in 
some cases where they are small and badly nourished the central 
cell does not divide at all. 
In addition to the one or two sperm nuclei that enter the 
archegonium the disorganized remains of the stalk and tube 
nucleus with their surrounding protoplasm are also swept in, 
along with what is left of the neck cells. Prothallial nuclei are 
also sometimes thrown in, and quite a collection of such hetero- 
geneous material may often be seen in the archegonial tip above 
the protoplasm of the egg. Most observers who have described 
the discharge of extra sperm nuclei or vegetative cells into the 
fertilized archegonium have made no distinction between entrance 
into archegonium and entrance into egg. Webber (’97) says that 
several spermatozoids may enter a single archegonium in Zamia, 
but that only the one that is used in fertilization actually enters 
the cytoplasm of the egg, the others remaining above and free 
in the cavity of the archegonial tip. Ikeno (’o1) calls attention 
to this point, and finds that in Ginkgo the supernumerary sperma- 
tozoids do not enter the cytoplasm of the egg, but remain dis- 
tinct from it, even if actually pressed into its surface. He also 
mentions the possibility that certain nuclei in the tip of the 
archegonia, that have in previous cases been described as derived 
from the sperm cell, are probably the results of amitotic division 
of a persistent ventral canal cell. These observations of Webber 
and of Ikeno I can positively confirm in Taxodium, The super- 
numerary aia cells remain separate from the cytoplasm of the 
ee, 
