294 Lawson . — The Gametophytes and Embryo of the 
and, as indicated in Fig. 29 , their chromatic contents come to resemble each 
other more closely as to their structure. As shown in this figure, the 
membrane between the nuclei persists for some considerable time. During 
the process of fusion the granular, starch-containing cytoplasm from the 
male cell completely envelopes both nuclei. In the great difference in size 
of the sex nuclei at the time when they first come together, Chamaecyparis , 
Thuja (Land, ’02), Cnpressus , Taxodium (Coker, ’04), and Cryptomeria 
(Lawson, ’04) present conditions similar to those found in the Abietineae 
(Blackman, ’98 ; Woycicki, ’99 ; Coulter and Chamberlain, ’01 ; Ferguson, 
’01 ; Miyake, ’03 ; Murrill, ’00), and in the Taxeae (Robertson, 5 04 ; Coulter 
and Land, ’05 ; Lawson, ’07). These conditions differ, however, from those 
found in Sequoia (Lawson, ’04), for here the male nucleus is quite large at 
the time of its entrance into the egg. 
In none of my preparations was I fortunate enough to find stages 
showing the formation of the first cleavage spindle, and I am therefore not 
in a position to give an account of the behaviour of the male and female 
chromosomes, or of the stage at which these elements lose their identity. 
From an examination of the early stages of the embryo in Thuja , Libocednts , 
Chamaecyparis , and Cupressus , I can say without much doubt that this 
spindle is organized in the middle region of the archegonium in just about 
the same place where the fusion of sex nuclei took place. In this I agree 
with Land’s (’02) observations on Thija occidentalism but cannot confirm 
Coker’s (’04) account of Taxodium , where the fusing nuclei are reported as 
sinking to the base of the archegonium before the first division occurs. 
The Embryo. 
In LibocedruSm Cupressus , Chamaecyparis , and Thija the first division 
of the fusion nucleus takes place near the centre of the archegonium. The 
two-free nuclei resulting from this division come to lie very close together, and 
are enveloped in a granular, deeply staining sheath which seems to consist 
mainly of starch. In this condition the first two nuclei of the pro-embryo 
move towards the base of the archegonium, as indicated in Fig. 30. It is 
very probable that some of this starch comes from the male cytoplasm, but 
that all of it comes from this source seems quite as improbable, for by the 
time the free nuclei have reached the base of the archegonium the amount 
of starch surrounding the pro-embryo has increased enormously. Fig. 32 
shows the pro-embryo of L ibocedrus with the two daughter-nuclei of the 
first division, each enveloped in a sheath of starch. Fig. 31 shows a little 
older stage of the pro-embryo of Thuja , where the starch surrounding the 
two nuclei has increased to such an extent that it seems to completely fill 
the basal region of the archegonium in which the embryo is about to be 
developed. When the conditions shown in Fig. 31 has been reached, the 
first two nuclei of the embryo prepare for mitosis, and as shown in Fig. 33 
