126 DEVELOPMENT OF THE FLOWER. 
change are not traceable in an early period ; the changed ones 
are green, oblong, more or less hispid bodies, concave interi- 
orly; the subsequent changes consist in their expansion and 
lobation; the back of each is away from the axis: owing to 
this and originally to their being transformed leaves, is due the 
almost invariable situation of the raphe which must, unless - 
some tortion of the funicle takes place, be next the axis. The 
raphe represents the midrib of the leaf, or its primary vein. 
This monstrosity teaches us several things, it shows a 
curious indisposition on the part of the stamina to become 
leaves, which from their near relation to petals in structure 
I should not have imagined would have existed. Even when 
changed they very often preserve some traces of their origi- 
nal structure, the limb being either oblique, or partly dis- 
coloured. The disappearance of the two short ones opposed 
to two sepals, may be taken as an indication together with . 
their smaller size, that there is always a tendency to imper- 
fection of the outer series. 
It teaches us the conformation of the pistillum, and the 
continuity of the stigmata with the placente. 
. It teaches us the nature of the ovula, which are beyond 
doubt transformations of leaves, it teaches us the reason why 
the raphe is always next the axis. Although I have not traced 
each step of the changes, I have no doubt that the outer tegu- 
ment is a leaf united along its margin, but always open to a 
greater or less extent at its apex. In this instance the direc- 
tion of the leaf corresponds well with that of the outer tegu- 
ment of the ovulum, no inversion can therefore be really said 
to take place in anatropous ovula, but the limb of the leaf is 
bent back on the funicle, with which its margins also cohere. 
The reason why the inner tegument is not vascular is due 
to its less development, there is no reason, however, why 
exceptions should not exist, and if they do, the vascular 
fascicle supplying it will be opposed to the raphe, because 
leaves alternate. 
An ovulum is therefore to all intents and purposes a bud, 
its coats are analogous to the tegument of a bud, and its 
nucleus to the apex of the axis. 
