150 ANDERSON: EMBRYOGENY OF MARTYNIA LOUISIANA 
On reaching the ovule, the pollen tube 
grows through the micropyle and enters 
the embryo-sac, sometimes a little to one 
side, crushing one or both the synergids. 
The tip of the pollen tube usually covers 
the egg-cell, thus obscuring the nucleus of 
the latter (Fic. 32). In some instances it 
seems that the tube enters the egg-cell at 
the upper end and transverses the entire 
length of it (Fic. 31). In all cases ob- 
served, there was evidence that the tube — 
had discharged the sperm nuclei in such 
a way that one of them came in direct 
contact with the egg nucleus (FIG. 30). 
Only the sperms and a little of the con- 
tents from the tip leave the pollen tube 
(Fics. 30 and 31). The fate of the 
second sperm nucleus was not ascertained, 
but it seems evident that it plays no part 
in the formation of the endosperm. The 
second sperm nucleus may not leave the 
Pes 
2 ae somes ts Oe — 
Ce ae ae 
ae 
ae 
= 
S Deg r~ 
= wr 
=< 
> 
RP aan tS 
geet, 
oe 
i Sas as 2 oO BF tr 
f 3. 
Hie tube, but this point can not be demon- 
et strated until some method of fixing and 
tana staining can be found that will reveal the 
= 
ee 
ies: : 
root presence of the nuclei among the granules 
{] 
A | 5 on Oy 8 
ineeren in the cytoplasm. The pollen tube in the 
micropyle and in the upper part of the 
ip 
eke 
embryo-sac retains its form and densely 
staining quality long after the embryo-sac 
is filled with endosperm (FIG. 35). 
The actual union of sperm and egg nu- 
cleus is similar to that in other angio- 
sperms. The instances of fertilization 
observed were similar to that of Lilium 
Martagon, figured by Mottier (4). For 
Verbena, Kanda (2) figures the sperm 
nucleus in contact with the egg-cell and 
speaks of it as fertilization. In all the 
fertilization stages observed in Martynia, 
Fic. 35. Embryo-sac filled with endosperm, 
xX 140. T, pollen tube; N, antipodali; E, embryo; 
U, suspensor. 
