20 Lawson.— -The Gametophytes , Archegonia , Fertilization , and 
position, and in the few cases observed the chromatin was in the spireme 
condition. From the fact that the first cleavage-spindle was frequently 
met with, and the fusion-nucleus in but a few cases, I conclude that a very 
short time intervenes between the conjugation of the sexual nuclei and the 
formation of the first cleavage-spindle. 
Before passing on to the events that follow fertilization, we have yet 
to explain what becomes of the second male cell in Sequoia. Being func- 
tional, but unlike the other Conifers mentioned above, it does not fertilize 
the same archegonium. In Pinus (Blackman, 1898) only one male nucleus 
is functional. This is also true for Cephalotaxus (Arnoldi, 1900), and 
probably for other Conifers. In these forms both male cells enter the 
same female organ, so that one pollen-tube can accomplish the fertilization 
of but one archegonium. In Sequoia sempervirens this is clearly not the 
case, for the two male cells of a single pollen-tube were found in the 
process of fertilizing two separate archegonia. The behaviour of the 
second male cell is a duplicate of that described for the first male cell. 
They discharge their nuclei into two neighbouring archegonia just about 
the same time. As each male cell functions in separate archegonia, we 
have in Sequoia a case where each pollen-tube may bring about the fer- 
tilization of two archegonia. As there are usually three or four pollen- 
tubes surrounded by a larger number of archegonia, and since each male 
cell fertilizes a separate archegonium, there may be as many as six or 
eight embryos developed. We shall see below that this generally happens. 
The Embryo. 
As stated above, very little time elapses between the fusion of the 
male and female nuclei and the development of the first cleavage-spindle. 
This spindle was frequently met with, and always found with its poles in 
the long axis of the archegonium. In some cases observed the chromosomes 
were at the equator, or on the way to the poles ; others again showed 
the daughter-nuclei already organized with the continuous fibrils con- 
necting them. One of the most noticeable features of the spindle is the 
large number of chromosomes as compared with the number present in 
the gametophyte. As in the gametophyte, the chromosomes are very long 
V-shaped structures, and after they have split and moved toward the poles 
they appear to be about half the size of the mother-chromosomes when 
at the equator. As near as could be estimated, there are about thirty-two 
chromosomes in the sporophyte and sixteen in the gametophyte. Fig. 32 
shows the first cleavage-spindle of the sporophyte with the large V-shaped 
chromosomes at the equator. 
The events following the first cleavage-spindle proved to be very 
interesting, because they differ so widely from those of other Conifers in 
which the early stages of the embryo have been investigated. In most 
