Embryo in Lilaea subulcita , II. B. K. 25 
two cells, a basal suspensor-cell which remains permanently 
undivided, and a terminal embryo-cell. 
8. The cotyledon is derived entirely from the terminal one 
of the primary segments into which the embryo-cell first 
divides. 
9. The stem probably always originates from the second 
embryonal segment, but this point is still somewhat doubtful. 
Its position is strongly lateral. 
10. The root is of lateral origin, in this respect differing 
from other Monocotyledons which have been studied. 
11. The root of the mature embryo is entirely like that of 
the older plant. 
Conclusions. 
From the study made of the development of the flower 
and embryo of Lilaea , it is clear that it shows resemblances 
to the other low Monocotyledons which have been studied. 
The apical origin of the sporangia is very much like that of 
Naias and Zannichellia , and it is quite probable that this 
will be found to be the case in other low types, such as 
Sparganium and the Potamogetonaceae ; but further investi- 
gations are necessary to determine this. 
The origin of the stamen and carpel in cases where they 
occur together, from the dichotomy of a common primordium, 
makes it probable that the resulting complex should be con- 
sidered as a secondary inflorescence composed of two flowers, 
rather than as an hermaphrodite flower. 
While the development of the embryo-sac is normally that 
of the typical Angiosperms, the occurrence of exceptional 
cases with a probable multiplication of the nuclei and the 
development of cellular tissue before fertilization is signifi- 
cant, especially in view of the similar phenomena in Naias , 
Z annichellia, and Sparganium , and suggests a possible case 
of reversion to a more primitive condition. 
The development of the embryo itself is most remarkable 
for the peculiar lateral origin of the root, which is quite 
