540 
MORPHOLOGY. 
BOOK VI. 
say, are an expansion of vegetation, and the flower a con- 
traction of it ; and in the flower itself, while the calyx is con- 
tracted, the corolla is dilated; the stamens again are con- 
tracted, and the pistil expanded ; and with the ultimate 
contraction of the ovules ceases the vegetable system. 
All that has hitherto been said of the pistil relates to it 
only in its simple state. In a state of composition it differs 
so much in appearance from its simple form, that all the old 
race of botanists was entirely ignorant of the true theory of 
its construction. No trace is to be found in the writings of 
Linnaeus of any thing which can be construed into an acquaint- 
ance with this subject : nor, excepting in Wolff's paper, can I 
find an indication of it in any writer before the appearance 
of Gothe. At section 78. of die Metamorphose der Pflanzen 
are the following remarkable words : — " Keeping in view the 
observations that have now been made, there will be no dif- 
ficulty in discovering the leaf in the seed-vessel, notwith- 
standing the variable structure of that part, and its peculiar 
combinations. Thus, the pod is a leaf which is folded up, 
and grown together at its edges, and the capsule consists of 
several leaves grown together ; and the compound fruit is 
composed of several leaves united round a common centre, 
their sides being opened so as to form a communication 
between them, and their edges adhering together. This is 
obvious from capsules, which, when ripe, split asunder; at 
which time each portion is a separate pod. It is also shown by 
different species of one genus, in which modifications exist of 
the principle on which their fruit is formed : for instance, the 
capsules of Nigella orientalis consist of pods assembled round 
a centre, and partially united; in Nigella damascena their 
union is complete." 
Having already spoken at length upon this subject, when 
considering the structure of the fruit, it is not necessary to 
repeat the arguments here. There is no doubt of the truth 
of the theory, which is now universally adopted by all philo- 
sophical botanists. 
As it may thus be proved that all the parts of a flower are 
merely modified leaves, there can be no difficulty in admitting 
the following propositions as the basis of morphology : — 
