CHAP. II. 
STAMENS. 
179 
rudimentary; the vesicles are in some species erect, in others 
decumbent, but in all cases more or less fibrous. (See 
Plate I. figs. 4. 18, 14, 15. 18, 19, 20.). For an elaborate 
treatise on the subject, see Joh. Ev. Purkinje de Cellulis An- 
therarurn Fibrosis: Vratislaviac, 1830, 4to ; with eighteen 
plates. 
The stamen deviates in a greater degree than any other 
organ from the structure of the leaf, by a modification of 
which it is produced ; and, at first sight, in many oases, it 
appears impossible to discover any analogy between the type 
and its modification ; as, for instance, between the stamen and 
leaf of a Rose. Nevertheless, if we watch the transitions which 
take place between the several organs in certain species, what 
was before mysterious, or even inscrutable, becomes clear and 
intelligible. In Nymphaea alba the petals so gradually change 
into stamens, that the process may be distinctly seen to depend 
upon a contraction of the lower half of a petal into the fila- 
ment, and by a developement 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. Qilillet. 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 developement, — 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- 
N 2 
