160 
ORGANOGRAPHY. 
BOOK I. 
upon a contraction of the lower half of a petal into the fila- 
ment, and by a development of yellow matter within the sub- 
stance of the upper end of the same petal on each side into 
pollen. A similar kind of passage from petals to stamens 
may be found in Calycanthus, Illicium, and many other 
plants. Now, as no one can doubt that a petal is a modified 
leaf, it will necessarily follow, from what has been stated, that 
a stamen is one also. But it is not from parts in their nor- 
mal state that the best ideas of the real nature of the stamen 
may be formed; it is rather by parts in a monstrous state, 
when reverting to the form of that organ from which they 
were transformed, that we can most correctly judge of the 
exact nature of the modification. Take for example that well- 
known double Rose, called by the French R. QEillet. In 
that very remarkable variety, the claw of the petals may 
at all times be found in every degree of gradation from its 
common state to that of a filament, and the limb sometimes 
almost of its usual degree of development, — sometimes con- 
tracting into a lobe of the anther on one side, or perhaps on 
both sides, — now having the part that assumes the character of 
the anther merely yellow, — now polliniferous, — and finally 
acquiring, in many instances, all the characters of an un- 
doubted though somewhat distorted stamen. Double Paeo- 
nies. Double Tulips, and many other monstrous flowers, 
particularly of an icosandrous or polyandrous structure, 
afford equally instructive specimens. It is for these reasons 
that it is stated in the Outlines of the first Principles of Bo- 
tany, 307., that " the anther is a modification of the lamina, 
and the filament of the petiole." * 
Such is the structure of the stamens in their perfect state. 
It often, however, happens that, owing to causes wdth which 
we are unacquainted, some of the stamens are developed 
imperfectly, without the anther and pollen. In such cases 
* Agardh considers a stamen to be composed of two leaves in a state of 
adhesion ; and that it is in fact a bud axillary to a sepal or petal. This 
is very nearly the opinion formerly entertained by Wolff. Endlicher 
adopts this view to a certain extent; and supposes the leaves to be 
rolled backwards, so that their under surface becomes the polliniferous 
part. But all this is mere hypothesis, unsupported by a tittle of evidence, 
and in opposition to the direct observations of Mirbel. 
