4i3 
Embryo of Sciadopitys verticillata . 
a little later stage, where the first neck-cell has divided into two and the 
central cell has enlarged to about twice its original size. It seems to be 
the rule among the Coniferales that the archegonia originate as superficial 
cells, but there are exceptions, as in Sequoia (Lawson, ’ 04 ) and Widdringtonia 
(Saxton, ’ 09 ), where some at least of the archegonia originate deep in the 
prothallial tissue. 
The nourishing jacket cells become differentiated quite early. In the 
very young stages they look very like the young central cell. They were 
frequently mistaken for archegonial initials. These cells, although they 
continue to multiply in number until the archegonium is mature, do 
not show any increase in size. Those surrounding the very young central 
cell presented the same dimensions and appearance as those associated with 
the more mature egg-cell. 
The number of archegonia developed varied from four to six, four 
being the number more commonly met with. They were always found 
situated at the apex of the prothalliurn, forming a single group, and their 
position in regard to one another is like that of Pinus> Abies , Psendotsaga , 
and Cephalotaxus , the individuals being separated by sterile prothallial 
tissue. In the mature state they are never as wide as the archegonia 
of the Abietineae, being rather narrow, long, tapering structures more nearly 
resembling those of Cephalotaxus . Each archegonium is surrounded by its 
own single layer of nourishing jacket cells. 
The young central cell enlarges very rapidly and elongates in a direction 
towards the centre of the prothallium. During the growth of the central 
cell its nucleus always remains directly under the neck-cells. The cytoplasm 
is quite coarsely granular and contains a number of small vacuoles. An 
early stage is shown in Fig. 41. The enlargement and downward growth 
of the cell continues, and, as shown in Fig. 42, the cytoplasm becomes 
charged with granules of food substance, evidently taken in through the 
jacket cells. As growth proceeds the vacuoles become larger and much 
more numerous, until, as illustrated in Fig. 43, the entire cell cavity takes on 
a frothy appearance in identically the same manner as it does in Cephalo- 
taxus , Pseudotsuga , Picea , and Abies (Miyake, ’03 ; Lawson, ’ 07 ). As more 
food substance gathers in the cytoplasm of the cell, the vacuoles appear to 
flow together, finally forming a single large one some distance behind the 
nucleus. Here, again, the archegonium differs from that of the Abietineae, 
for among the latter there is no large vacuole, either in the central cell or 
the egg-cell. 
As shown in Figs. 40, 41, and 42, during all the early stages of the 
archegonium the neck-cells are superficially placed in regard to the apical 
surface of the prothallium. This condition, however, is soon changed, for 
all of the sterile tissue at the apex grows forward for a considerable distance, 
leaving an open canal leading to the neck of each archegonium. These 
