434 Lawson . — The Gametophytes , Fertilization and 
forms the chromatin of the male and female nuclei may be distinguished 
inside the wall of the female nucleus ; the fusion of the two taking place 
very slowly. In Cryptomeria the process of fusion is more rapid. As 
shown in Fig. 45 , the male and female nuclei only retain their identity 
by the presence of the nuclear membrane between the two. The chromatin 
contents of the nuclei are structurally alike, and as soon as the membrane 
separating them breaks down the male can no longer be distinguished from 
the female. In this particular process, Cryptomeria resembles Sequoia. 
When the membrane between the nuclei disappears, the chromatic contents 
of the two mingle together and form the common network of the fusion- 
nucleus. The fusion-nucleus was frequently met with, and this has con- 
vinced me that there is at least a short resting period before the organization 
of the first segmentation-spindle. Fig. 49 shows the fusion-nucleus with 
the chromatin evidently in the resting condition. It has been reported that 
in Taxodium (Coker, ’03) and in Taxus (Jager, ’99) the fusing nuclei 
travel to the base of the egg before the first division occurs. In Crypto- 
meria this is clearly not the case, for the first segmentation-spindle was 
always found at the centre of the egg, just about the point where the fusion 
of the nuclei took place. 
It has been stated above that each fertilized archegonium receives but a 
single male cell, although there are two of the latter formed in each pollen- 
tube. We have now to complete the history of the second male cell. 
In many Conifers, especially in those forms where the entire contents of the 
pollen-tube pass into the archegonium, only one of the male cells is 
functional. This has been observed in Pinus (Blackman, ’98), Cephalo- 
taxus (Arnoldi, ’00), Picea (Miyake, ’03), Podocarpus (Coker, ’02), and it 
may sometimes occur in Taxodium (Coker, ’03). In these cases a pollen- 
tube can bring about the fertilization of but one archegonium. In other 
forms where both male cells are functional, as in Juniper us (Strasburger, 
’79), Sequoia (Lawson, ’04), and generally in Taxodium (Coker, ’03), two 
archegonia may be fertilized from the contents of one pollen-tube. In 
Cryptomeria , where so many male cells from the various pollen-tubes 
are gathered together in the depression immediately above the archegonium- 
complex, it was difficult to distinguish the second male cell from those 
of the other tubes, as they are all of the same size and shape. As nearly 
all of the archegonia were fertilized, however, it seems extremely probable 
that both male cells are functional, and that two archegonia are fertilized by 
one pollen-tube. 
The Embryo. 
Although the fusion of the male and female nuclei results in a distinct 
resting fertilized nucleus, the resting period is a short one. The uniform 
chromatin network of the fusion-nucleus very soon undergoes a change 
