168 
CONTRIBUTIONS TO BOTANY. 
Hating from the placenta, while in Halesia they are wholly free 
and attached by a point. 
The growth of the ovary in Styrax and Strigilia, as before 
mentioned, is confined entirely to the upper portion, while the 
lower moiety remains of its original length. In Halesia, the re- 
verse is observed ; for at the same time that the upper moiety 
continues quite stationary, appearing afterwards like the swollen 
base of the style, the lower half acquires a gradual increment, 
until, by the period the fruit is perfected, it attains at least 
twenty times its former length and breadth. The changes that 
occur during this growth may be noticed distinctly about a 
montli after the fall of the corolla, by which time the ovary has 
acquired double its former proportions. On making a section 
of the ovary at this period, it will be found that, owing to the 
much greater increment of its basal portion, the placenta, instead 
of appearing to originate, as formerly, from the very bottom, is 
now elevated considerably above the base of the central space, 
and one, two, or three of the incomplete cells are seen raised up 
with it, and affixed against the inner surface of the main cavity, 
like parietally suspended sacs, each containing one of its ovules 
greatly increased in size, with the abortive ones unchanged, 
while the fourth incomplete cell disappears entirely, so that the 
ovary now seems completely unilocular from top to bottom, and 
with one, two, or three ovuligerous open sacs parietally attached 
1o its inner wall. 
At the period of four months after the fall of the corolla, I 
found the ovary increased to ten times its original size; the 
ovules were in the same parietal position as last described, but 
their sacs, formerly open, were now enclosed and covered over, 
one with a bony coating, apparently an extension of the shell of 
the pericarp, now hardened by osseous deposits ; the other cells 
or sacs, not destined to perfect their ovules, were also entire and 
enclosed, but the covering here was membranaceous and not 
ossified. I observed that sometimes two, or all three, of the cells 
became osseous, and produced perfect seeds. The entire cavity 
of the main central space, at this period, was filled with a soft 
white mass of light cellular tissue, which, after two or three days^ 
exposure to the air, when cut open, gradually dried and shrank 
into a very thin membrane, lining the now hollow cavity of the half- 
matured fruit. At that period, if only one cellule became osseous, 
it contained an enlarged ovule, which, though not yet arrived at 
maturity, clearly exhibited its two distinct integuments, as well 
as its chalaza, raphe, and embryo ; the other two membranaceous 
cellules contained each a considerably enlarged, though withered 
ovule, seeming as if it had lost its vitality at some intervening 
period. Upon the ventral side of these cellules as many distinct 
