Structure, etc., of Epiphegus Virginiana. 381 
In immature ovaries, there is a considerable empty space 
in the centre of the cavity. In later stages the ovules have so 
enlarged as to entirely fill the ovary. They lie in a uniform 
structureless, faintly stained matrix. Starch is quite abun- 
dant in the walls of the young ovary, and gradually increases 
in amount in older ovaries. But in the mature capsule there 
is relatively little present. It has probably been used up in 
the growth of the ovules. 
As the ovules grow and fill up the cavity, a considerable 
tension is brought to bear on the walls of the ovary. The 
outer cells of this wall assume a stretched-out, flattened 
appearance, and frequently are torn completely away. This 
tension produces the vertical split that occurs lengthwise 
across the summit of the ovary. In a still later stage, the 
entire tissue of the ovarian wall has assumed a stretched-out 
appearance. But the inner cells of the wall, on each side of 
the longitudinal split across the capsule, have enormously 
enlarged and become crowded with starch grains. Very 
little starch is now present elsewhere in the ovary. Now the 
action of the valves in dehiscing is to pull apart and curl 
their edges outward and downward. And the downward 
pull of the stretched ovarian wall, together with the out- 
ward growth of the two swollen cushions along the split 
edges, would produce this rolling of the valves outward and 
downward. 
The Nectary.—This is present alike in the cleistogamic 
and the evident flowers. It is generally similar in each, but 
is somewhat smaller in the cleistogamic flower, especially 
so in somewhat later stages. It appears as a swelling on one 
side of the ovary, antero-laterally in position just above the 
base (Fig. 5). Neither its depth nor its thickness is very 
great, but it has considerable length, running half-way 
round the ovary in chasmogamic flowers. It is not so long 
on the cleistogamic ovary. 
The nectary consists of a kind of tissue, strikingly unlike 
the surrounding cells in general appearance. It consists of 
