150 BOTANICAL GAZETTE [AUGUST 
appearance to that described for the polar nuclei and the second 
sperm nucleus. The chromatin is in strands, that of the sperm 
being heavier than that of the egg (fig. 1). The sperm fertilizing the 
egg is very much smaller than the sperm uniting with the polar 
nuclei at the time of contact and not so vermiform (compare figs. I 
and 17). Fig. 2 illustrates a typical fertilized egg of Trillium 
grandiflorum just a little later in development than that of Lilium 
(fig. 1). In this later stage the chromatin is lumpy, the particles 
being larger in the sperm than in the egg, and the membranes sepa- 
rating the two nuclei are becoming very thin, so that it is difficult 
to distinguish them at all times. After this time these membranes 
are rarely to be found, although in some instances they persist for a 
longer period (fig. 4). 
The chromatin gradually collects into larger groups, forming 
more or less broken threads connected with each other by fine 
anastomoses (figs. 3, 4). In many portions of the nucleus of this 
fertilized egg the parallel nature of some of these strands is quite con- 
spicuous (figs. 3,4). In some fertilized eggs, as for example in fig. 5, 
a more or less beaded, although discontinuous, spirem was noted. 
Even though the nuclear membranes which separated the egg and 
the sperm have disappeared, the chromatin that has been contrib- 
uted by each of the two nuclei remains distinct (fig. 3). This con- 
dition is much more evident in some fertilized eggs than in others. 
The sperm at the period of union contains a much smaller amount 
of chromatin than the egg and throughout most of the subsequent 
stages this condition persists (figs. 3, 4, 9,10, 12). During all this 
time the fertilized egg is growing in size and increasing the amount 
of chromatin. When the continuous spirem is first formed, it is 
quite thin (fig. 6), but as the prophase advances the chromatin 
thread thickens and shortens until a comparatively thick spirem 
results (figs. 6-12). Instead of one continuous spirem, two distinct 
spirems are usually to be seen within the single nuclear cavity, 
although located in different parts of the cavity (figs. 8-10). In 
some sections such differentiation is not visible (figs. 6, 7). The 
dotted lines a—b in figs. 9 and 10 separate the two spirems, one of 
which was contributed by the sperm, the other by the egg. 
In spite of the fact that a nucleolus is not seen in the sperm 
when it unites with the egg, very small ones are found in later 
