176 ANGIOSPERMS. 
embryo-sac and can be distinctly recognized, no trace of the cytoplasm 
which accompanied them in the tube can be distinguished, so that 
the exact behavior of this cytoplasm is unknown. Consequently we 
are concerned here solely with the union of the nuclei. 
THE FUSION OF MALE AND EGG-NUCLEI. 
We shall follow first the male nucleus which fuses with that of the 
egg-cell. It is presumably the first male nucleus which escapes from the 
pollen tube that unites with the nucleus of the egg, but positive proof 
on this point is want- 
ing. Incertain spe- 
cies of Lzlium, and 
various observers 
have shown this to be 
true of many other 
Angiosperms, the 
male nucleus, when 
observed in the egg- 
cell, is frequently 
sausage-shaped, 
worm-like, or S- 
shaped (Mottier, 
797), making one or 
more spiral-like 
turns, which is sug- 
gestive of a worm- 
like motion, but posi- 
Fic. 74:—Fusion of sexual nuclei, i 
A, vermiform male nucleus applied to egg-nucleu$, Lilium martagon. tive proof of any such 
B, egg-cell of Lilium candidum, showing sexual nuclei inact of fusing; movement is want- 
the nuclear membranes have disappeared at place of contact. 
ing. It applies itself 
to the nucleus of the egg, retaining the form mentioned for some time 
(Fig. 74, A). The structure of the two sexual nuclei at this stage is 
accurately shown for L2léum martagon in this figure. The two 
nuclei are in the resting condition, although the chromatin of the 
male nucleus is a little more regularly arranged. The male nuclei 
when in the embryo-sac stain a deeper red, safranin, gentian violet 
and orange G being used, than the other nuclei of the sac, and for 
that reason they may be readily recognized. As fusion progresses, the 
nuclei become quite alike in shape, size and structure (Fig. 74, B). 
Their membranes gradually disappear at the place of contact, their 
cavities become one, and the resulting fusion nucleus, which is in the 
