i?3 
Pseudotsuga Douglasii . 
established before the prothallium is formed. The conditions in Pseudotsuga , 
however, suggest those in the Araucarineae (Thomson, ’05 ; Lopriore, ’05), 
but unlike the latter there are no additional free nuclei in the tubes. The 
development of the pollen-tubes in a position so far removed from the nucellus 
is no doubt a specialization to meet the peculiar pollen-receiving device. 
Correlated with the position of the pollen-tubes in Pseudotsuga there is 
an early disintegration of the tissue of the apex of the nucellus. The 
cells in this region of the nucellus separate from one another in places, and 
there appears to be a general breaking-down or dissolving of the tissues in 
advance of the descending pollen-tubes. These latter structures, therefore, 
find no obstructions in their path. There is no firm tissue to penetrate 
before reaching the archegonial chambers. Indeed, at the time of fertilization 
the apex of the nucellus is completely broken down, and we find an appear- 
ance very unlike that of Pinus and the majority of other Coniferales where 
the nucellus persists for some time after fertilization. 
As in other Abietineae the archegonia are so arranged that the necks 
are separated from one another by sterile prothallial tissue and each arche- 
gonium has its own archegonial chamber. By this arrangement the tip of 
the pollen-tube enters an archegonial chamber and its entire contents are 
discharged into the egg. It is therefore possible for one pollen-tube to 
fertilize but a single archegonium. It was noticed that the depth of the 
archegonial chambers was not as great as that in Tsuga, and the number of 
neck-cells is also less (Murrill, ’00). In fact there is a considerable difference 
in the appearance of the archegonial group of the two genera. This seems 
to be in harmony with Jeffrey’s (’05) conclusions that Pseudotsuga is more 
closely related to Larix , Pice a, and Pinus than it is to Abies , P seudolarix , 
Cedrics , and Tsuga . 
By the time the egg nucleus reaches its central position, after the 
organization of the central canal cell, it becomes very much enlarged. This 
enlargement is indicated in Figs. 29, 30, and 32. During this period the egg 
cytoplasm loses its ‘ frothy ’ or vacuolate appearance, and becomes very 
coarsely granular by the presence of numerous so-called ‘ proteid vacuoles ’. 
As the egg-nucleus approaches its mature size, and prepares for fertili- 
zation it takes on a very extraordinary appearance due to the presence of 
several dense masses of cytoplasm which seem to project at intervals into 
the interior of the nucleus. As a matter of fact these masses do not project 
into the nucleus but are contained in small indentations or pockets which 
give the nuclear membrane a very irregular outline in the manner shown 
in Fig. 31. These masses of dense cytoplasm proved to be quite interesting 
and important because it was found that one or more of them take, eventu- 
ally, an active part in the formation of the fibrils of the spindle immediately 
following fertilization. This has thrown considerable doubt on the state- 
ment repeatedly made (Blackman, ’98, Murrill, ’00, Ferguson, ’05, and others) 
