1902] GAMETOPHYTES AND EMBRYO OF PODOCARPUS 95 
lying in contact with it below. Another small nucleus was 
present in addition to the tube nucleus. In this case the pollen 
tube had reached the prothallium before the archegonia initials 
could be distinguished from their neighbors. I have found this 
to be also the case in both Taxodium and Taxus, when the pol- 
len tubes reach the embryo-sac before the beginning of cell for- 
mation. In the Abieteae the tubes reach the archegonia only 
a few days before fertilization. On reaching the prothallium 
the pollen tube spreads out to an unusual extent. When only 
one is present it may cover almost the whole tip of the prothal- 
lium and send down short spurs on the sides. 
Only two cases were found showing the male cells, but these 
leave no doubt that there is only one functional male cell formed, 
asin Taxus. Figs. 13-16 are sections through the same pollen 
tube, 73-15 being serial. The male nucleus nearest the tip has 
appropriated all of the protoplasm, leaving the other thrust 
almost entirely out of the cell, and naked on its outer surface. 
The difference in the structure of the two nuclei is also marked. 
The functional one has the usual structure of the male nucleus 
se Symnosperms—a very dense, close-meshed linin reticulum, 
difficult to stain, which, except in very thin sections, almost hides 
the nucleolus. The latter is not shown in the figures, but appears 
im another section. In both Podocarpus and Taxodium I can 
confirm Miss Ferguson’s (1901, 2) statement that there isno meta- 
_ Plasmic substance in the male nuclei. An irregular nucleolus is 
always present. It is the only part of the nucleus that. takes 
the Saffranin stain, and_ this, together with its evidently 
el pao nature and in Taxodium its behavior in fertiliza- 
iis avinces me that it is composed of chromatin. ee 
a: extruded nucleus shown in figs. 13 and 74 has appar- ae 
ue Bag eS the same developmental changes as serge ae 
‘won was eae PRONE has splnsineen css cS a 
oo egeneration are unmistakable. — ee 
nei _Protoplasm of the male cell consists of a denser inner — 
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