CHAP. IT. 
OVARY. 
175 
edges {Jig, 133.) : in that case the placentae do not project 
at all into the cavity of the ovary, but are still more strictly 
parietal than the last. 
132 133 134 
Another class of anomalies of a still more remarkable cha- 
racter, is that in which the dissepiments are obliterated, while 
the placentae remain a distinct mass in the centre of the 
ovary, as in Lychnis ; forming what is called a free central 
-placenta {Jig. 132.). But, if we examine these plants at a very 
early period of their formation, long before the flowers expand, 
the explanation of the anomaly will be obvious. Such plants 
are, at that time, constructed upon the ordinary plan, with 
their dissepiments meeting in the centre and forming there a 
fungous placenta ; but subsequently the shell of the ovary 
grows more rapidly than the dissepiments, and breaks away 
from them ; while the excessive growth of the placenta after- 
wards destroys almost all trace of them : their previous pre- 
sence is only to be detected by lines upon the shell of the 
ovary, or by a separation of the mass of ovules into distinct 
parcels upon the placenta. 
All partitions whose position is at variance with the fore- 
going laws are spurious. Such spurious dissepiments are 
caused by many circumstances, the chief of which are the 
following : — they are caused by expansions of the placenta, 
as in Cruciferae, when they form a partition stretching from 
one side to the other of the fruit ; or they are mere dilatations 
of the lining of the pericarp, as in Cathartocarpus Fistula, in 
which they are horizontal ; or they are internal expansions of 
the dorsal or ventral suture, as in Amelanchier, Astragalus, 
and Thespesia, in which they are distinguishable from their 
dissepiments by not bearing the placentae, and by being op- 
posite the stigma, or by projecting beyond the placentae ; or, 
finally, they are caused by the sides of the ovary projecting 
