Pseudotsugci Douglasii. i 7 1 
Pimis , Pice a, Abies , and other Conifers. The primary neck-cell shows little, 
or no further increase in size but very soon divides by an anticlinal wall. 
The two cells thus formed may undergo division by periclinal walls to form 
two tiers of cells in the neck. In many archegonia, however, especially in 
the later stages of development, but a single tier of cells could be found. 
This confirms the observations of other writers (Murrill, ’00 ; Coulter and 
Chamberlain, ’01 ; Coker, ’02 ; Ferguson, ’ 04 ), that the variation in the 
number of neck-cells is quite common among the Coniferales. 
The central cell increases in size quite rapidly and its elongation is 
directed towards the centre of the prothallium. It is at first vacuolate, with 
a large nucleus and granular cytoplasm. Later, the small vacuoles become 
so numerous that the cytoplasm takes on a frothy appearance quite like that 
of certain other Abietineae (Miyake,’ 03 ) and Cephalotaxus (Lawson, ’ 07 ). 
At a very early stage in the development of the central cell a single 
layer of jacket cells becomes organized. This nourishing sheath appeared 
in all respects similar to those already fully described for other Abietineae. 
It is, however, a significant fact that the original cells of the jacket in many 
of the Abietineae make their appearance simultaneously with the arche- 
gonial initials. In certain cases it is only their relative position which allows 
us to distinguish between the primary jacket cells and the archegonial 
initials at these very early stages. 
Stages in the development of the central cell are shown in Figs. 18, 19, 
so, 31. The nucleus, although very large, remains in the vicinity of the 
neck. The sterile tissue at the apex of the prothallium continues to grow 
forward, leaving a free passage to the neck of each archegonium. This 
passage or archegonial chamber is, however, not very deep — resembling 
more closely the conditions found in Pimis , Picea , and Larix than those 
described for Tsuga (Murrill, ’ 00 ). 
The largest number of archegonia found in one prothallium was six. 
The number seems to vary from four to six. Four, however, was the corn” 
monest number met with. They are situated quite closely together (Figs. 
37 and 38), there being very little sterile tissue between them. Although 
the necks are separated from one another by a considerable amount of tissue, 
they may come in contact with one another in the middle region where they 
are widest. This condition may be seen in Fig. 38. This figure also 
illustrates the fact that the archegonia are much longer in proportion to 
their width than is the case in Pinus y Picea , Larix , or Tsuga. The form 
they present in cross-section is shown in Fig. 37. 
The archegonium reaches nearly its mature size before the central 
nucleus — which retains its position near the neck-cells — shows any further 
activity. But from the material collected upon June 3 many evidences of 
nuclear activity were found in the central cell. Transition-stages from the 
reticulum to the spireme, and from the spireme to the definite chromosomes, 
