i5 
E antes. — The Morphology of Agathis australis. 
usually be detected even before the eggs are mature, and after fertilization 
it goes on rapidly. One large central area usually suffices for all the 
archegonia, but where two crowns of eggs are well separated such a region 
is formed for both. The changes are these : the cytoplasm becomes more 
dense ; the nuclei, of which there may already be several, increase in 
number, often forming clusters of three to eight Division is amitotic, the 
small nuclei becoming elongate and then fragmenting. Great increase in 
size follows. Then starch grains appear. In the cell contents of the rest 
of the endosperm no change has occurred at this time. 
Elongation of the suspensors forces the embryo and its cap downward, 
as usual in the Conifers. The course taken is not direct. The path of 
least resistance — that along the radial rows of endosperm cells — is followed 
until the central line of the gametophyte is attained. Then the core of 
suspensors coils, forming a close spiral. This also is a common feature of 
coniferous embryonic development. It may be due to increased resistance 
to progress, or to the food-supply stored in this region, the coils of the 
suspensors becoming absorptive, and causing widespread cell destruction, 
since behind them in the archegonium they have no supply of nourishment 
for their growth. Beyond this point the suspensors extend straight down 
to the final position of the embryo. Fig. 6 shows the complete course 
followed by the suspensors ; the remains of the archegonium — very dark — 
on the upper right side ; the first section of the suspensors, the coils of the 
central spiral loose in a large eroded cavity, and the straight lower section 
tipped with the embryo. 
The suspensors form a fascicle, cylindrical or somewhat angular, and 
are generally firmly compacted. Fig. 8 shows transverse sections of the 
bundle in the spiral region. The firm walls are noticeable. No evidence 
was seen of any splitting within the bundle such as results in polyembryony 
in Cephalotaxus^ Dacrydium , Cryptomeria , and perhaps other genera. The 
cap would naturally hinder any budding of this sort from the embryo. 
Only a single embryo ever develops from the egg. But frequently several 
archegonia are fertilized, and as a result a number of embryos may start 
downward. Their suspensor coils snarl together, and that with the strongest 
bundle is alone able to pass directly down to the central situation. The 
others lose their courses and pass out laterally or even back upon their 
track, slowly going to pieces. 
The embryonic cap remains wholly unchanged from the time of its 
maturity until the growth of the suspensors is complete. During its 
transportation the cells of the true embryo are also dormant, but imme- 
diately upon arrival at the end of the course rapid development ensues. 
The cap and the base of the suspensor core give up their contents, probably 
being absorbed as nutriment together with the surrounding cells. Fig. 32 
shows the tip of the suspensors forcing the cap and the embryonic tier 
