342 
Campbell. — Studies on the Araceae , III. 
of cells may have belonged to two closely appressed sacs, but this does 
not seem to have been the case. 
It is evident from the foregoing statements that there is remarkable 
diversity in the embryo-sac structures in Nephthytis. How far these 
are normal cannot be certainly determined until material grown under 
natural conditions can be examined. As the variations find a pretty close 
counterpart in those of Aglaonema commutation , it is highly probable that 
some of them, at least, are normal deviations from the type found in most 
Angiosperms. The most significant variations are the greatly increased 
number of nuclei, the occasional multiple nuclear fusions, and the less 
marked polarity of the embryo-sac. 
Fertilization. 
Although numerous attempts were made to find fertilization stages, 
these met with indifferent success, and even where what seemed to be 
the pollen-tube could be demonstrated, the real condition of affairs could 
not be satisfactorily made out. 
Two cases are shown in Figs. 63, 6 4, and 70. In 63 there were no 
antipodal cells, but in the cavity of the sac there were three large nuclei, 
two of them (see Fig. 62) in a resting condition, and surrounded by starch 
granules, the upper one somewhat smaller, and evidently in the early 
prophase of division. At the apex of the sac were two large cells (without 
cellulose membranes), presumably the egg-cell and a single synergid. The 
latter was much more granular, lay at the apex of the sac, and its nucleus 
was smaller than that of the clearer egg, which was placed below it. 
Closely applied to the synergid (perhaps passing through it), and 
extending to the egg, was an irregular body ( p.t .), staining strongly with 
gentian violet and looking like a pollen-tube. Within it was an irregular 
darkly staining body, which may have been one of the generative nuclei. 
Apparently within the egg, but quite free from the egg-nucleus, was 
a smaller nucleus which probably was the second generative nucleus. 
A quite different case is shown in Fig. 70. At the apex of the 
embryo-sac was seen an irregular sac-like structure which seemed to be 
connected with a tubular body (pollen-tube) pushing between the cells at 
the apex of the embryo-sac. In this were two conspicuous nuclei which 
may possibly have been generative nuclei, but the whole structure differs 
much in appearance from the ordinary pollen-tubes. A second less definite 
but similar pollen-tube was present. The sac contained an egg-cell at 
the apex, and six (possibly seven) other nuclei. Of these, two showed 
some indications of fusion. 
Beyond these very unsatisfactory observations no light could be 
thrown upon the processes of fertilization. 
