2 
Though of different origin the material was of absolute uni- 
formity as to megaspore- and embryosac formation. KuyPER’s 
material however showed some delay in development. Ovaries 
of a size in which usually mature sacs are found, contained 
but tetrads or exceptionally a two-nucleate stage. This delay 
is distinct from the beginning, the nucellus remaining without 
any differentiation until an exceedingly advanced (Plate I, 
Fig. 3) and far later stage than usual in all other material. 
The examination of many thousands of sacs underlies this 
publication, but never anything has been seen, which was not 
in conformity with the following description of the development 
of the female gametophyte. 
The Megaspores. 
Ordinarily the archesporium is distinguishable about the time 
of the first differentiation of the integuments. It is onecelled 
and hardly to be recognised from the cells of the surrounding 
nucellar tissue. (Plate I, Fig. 1). Occassionally a two celled ar- 
chesporium is met with (Plate I, Fig. 2), both cells showing the 
same germinating capacities, which might lead to two tetrads 
and even to two complete embryosacs lying paralel. 
The archespore cell does not divide and is the embryosac 
mothercell (Plate I, Fig. 4). Parietal tissue is totally suppressed, 
but exceptionally archespore cells containing two nuclei are 
met with. (Plate I, Fig. 5, 6). In no case were cell walls seen. 
The embryosac mothercell gives rise to two cells of unequal 
size, a large inner one and a small outer cell (Plate I, Fig 7). In 
the second division the spindle of the outer cell lies rectangular 
to the axis of the sporangium. Thus the four megaspores are 
never found in a row, but always the two outer cells at a 
right angle with the inner ones (Plate I, Fig. 8). 
Megaspore formation is followed by a rapid desintegration and 
final disappearance of the outer cells, The first signs of destruc- 
tion are already seen when the functioning inner one is still one- 
nucleate and has hardly begun to grow (Plate I, Fig. 9) and even 
before the end of the two-nucleate stage has been reached their 
disappearance is complete (Plate I, Fig. 12, Plate II, Fig. 18). 
oe 
