968 T ho day and Ber ridge. — The Anatomy and Morphology of 
three or four in number, with a corresponding number of vascular bundles 
in the outer integument. The angles are not very prominent, but it is quite 
easy to tell their number by examination with the naked eye. 
In the outer integument there is an outer soft and an inner fibrous layer 
as in E. distachya. In the outer layer the hypodermal brown tissue is only 
differentiated in the extreme base of the outer integument, where it forms 
a ring, and in the tip, where it is distributed in bands alternating with the 
vascular bundles. Text-fig. XI. i shows one of these bands cut longitu- 
dinally on the right side of the ovule, while on the left the section has passed 
through the region in between the bands and has cut one of the alternating- 
vascular bundles. The inner fibrous layer is relatively less thick than in E. 
distachya ; probably this is correlated with the abundant development of 
sclerenchyma throughout the outer parenchymatous layer (Text-figs. XI. i, 
and x). The strands of fibres described in E. distachya accompanying the 
vascular bundles in the apical region of the ovule are differentiated here also, 
but are strongly lignified at a much earlier stage (FS, Text-figs. XI. i, and Xil). 
The vascular bundles have less transfusion tissue than in E . distachya. 
The inner integument differs only in the fact that in the fertilized seed 
the tip of the micropylar tube is sometimes coiled over, and that reticulately 
thickened strengthening cells 1 are scattered through the base of the thin free 
portion below the micropylar tube (Text-fig. xi. 4). 
The mass of hardened mucilage closing the apex of the micropylar 
tube was particularly well seen in this species (Text-fig. XI. 3). 
(f) The Development of the Ovule. 
The development of the ovule has been already described by other 
authors, and it is not proposed to give any details here, but merely to draw 
attention to the relations of the growth of the various parts of the ovule at 
each stage of development. 
In the very young ovule the two integuments arise close together at 
the base of the ovule; - at the stage shown in Text-fig. xm. 1 the bases 
of the two integuments are still almost on a level. From this stage onwards 
for some time the growth is mainly confined to the free apex of the nucellus, 
while very little development takes place in the region between the levels 
of origin of the two integuments. It will be seen that in Text-fig. xm. 2, 
which is clearly a much older ovule than Text-fig. XIII. 1, this region 
has not begun to develop. Growth here begins about the time of cell- 
wall formation within the megaspore and continues with the enlargement 
of the prothallus ; in the ovule figured in Text-fig. XIII. 3, which is not 
yet fertilized, considerable growth of this region has taken place. From 
this stage onwards the nucellar apex enlarges less in proportion to the rest 
1 It is probable that these were the cells once mistaken for tracheides. See reference in Thoday, 
1911, p. 1117, note 3. 
2 See Fig. 2, PI. XXII, in Berridge and Sanday, 1907. 
