332 
Campbell ' — Studies on the Araceae y III. 
fusion were not followed, but there was nothing to indicate that the process 
differed in any respect from the usual one. The endosperm-nucleus 
resulting from this fusion is, at first, not markedly different, except for its 
greater size, from the polar nuclei ; but it subsequently enlarges a good deal 
and the chromosomes become more evident, preparatory to its entering 
upon the first prophases of division. 
At the time the embryo-sac is ready for fertilization (Fig. 14) the egg- 
apparatus shows the two similar synergidae at the apex, with the egg-cell 
somewhat lower down. The egg has less granular cytoplasm and its nucleus 
is somewhat larger and does not stain so readily as do the synergidal 
nuclei. The arrangement of the antipodal cells, as is so often the case, is 
very much like that of the cells of the egg-apparatus, but the three cells 
are entirely similar as to their contents. 
As the embryo-sac approaches maturity, the lateral tissue of the 
nucellus is almost completely destroyed, and the sides of the embryo-sac 
are separated from the inner integument of the ovule only by the remains of 
the nucellar tissue. The apex of the nucellus, as in most Araceae examined, 
persists as a conspicuous cap covering the apex of the embryo-sac 
(Fig- 15 )- 
Fertilization. 
While a few preparations showed the entrance of the pollen-tube, the 
details of fertilization could not be treated as fully as could have been 
wished. 
It is possible that the conspicuous papillate glandular hairs at the 
base of the funiculus are concerned in directing the growth of the pollen- 
tube to the micropyle. The pollen-tube pushes down between the cells 
of the nucellar cap, and apparently penetrates one of the synergidae. In 
the specimen shown in Fig. 15, the synergid into which the pollen-tube 
seemed to have penetrated was decidedly more granular in appearance 
than the other one, and was probably being destroyed by the growth of the 
pollen-tube through it. The most satisfactory preparation that was found 
is shown in Fig. 17. In this case the pollen-tube had crowded between 
the synergidae, one of which remained intact while the other was much 
contracted and the nucleus had lost its regular contour. It was not 
certain whether or not the pollen-tube had really penetrated the synergid, 
or merely was appressed to it. Apparently within the tube was an 
irregular deeply stained body ( t.n\ which it was concluded was the tube- 
nucleus. Two much smaller nuclei, d* 1 , < 3 2 } outside the tube and 
presumably discharged from it, were interpreted as the two generative 
nuclei. One of these, with clearly defined contour and a conspicuous 
nucleolus, seemed to be within the egg, while the other, which stained more 
