(344) 
has become entirely cellular, a mass of loose tissue whose 
outer surface is composed of a layer of cubical or tabular 
cells. 
The embryo does not materially differ from those of sev- 
eral other forms examined. An earlier stage than that rep- 
resented by figure 77 was not observed. Here can be seen a 
short suspensor with some longitudinal divisions and the epi- 
dermis marked off to some degree. The subsequent growth 
of the embryonic mass results in the assumption of a pyriform 
shape, which gradually gives way to a more rounded form. 
The cotyledons appear at a slightly later stage, when the 
distal portion of the mass becomes somewhat flattened. The 
differentiation of structures at the apex of the radicle does 
not appear, however, until some time later, as shown in fig- 
ure 42, in which the root-cap and dermatogen may be distin- 
guished. At the stage represented in figure 39 the form of 
the ovule is materially changed. It elongates rapidly during 
this period and when the early embryonic differentiation ap- 
pears (jg. 43) has practically assumed the proportions of a 
ripe seed. 
Bryonopsis 
In the case of Bryonopsrs there arises a single row of 
ovules upon each flank of the placenta. Beneath the apex 
of the incipient nucellus the spore-mother-cell may be found 
at an early stage. Although an entirely complete series of 
the early stages was not obtained, the conditions that were 
observed indicate that the spore-mother-cell arises in the 
usual way. In the earliest stage observed but two tapetal 
cells were found separating the mother-cell from the overly- 
ing epidermis. Figure 4g shows a condition slightly later. 
About this time the inner integument may be detected arising 
from the epidermis in a ring below the apex of the nucellus. 
By the periclinal divisions of the tapetal cells and those 
adjoining, the spore-mother-cell soon becomes centrally situ- 
ated in the nucellus (jg. 45). It also becomes considerably 
elongated and soon divides into four megaspores of which 
the lowermost is the functional one (fg. 46). The three 
