A76 GENERAL MORPHOLOGY. 
erowth up to a certain point and is then stopped, and 
thus changes are brought about in the part affected 
of a different nature from those dependent on non- 
development or suppression. 
Some malformations are congenital, therefore, while 
others are acquired—in the former instance the dis- 
turbance is coeval in origin, and contemporaneous in 
its growth and development, with those of the affected 
part; in the latter case the organ may have attained 
its ordinary degree of perfection, or at least may have 
advanced some way towards it, before any deviation 
shows itself. True chorisis or fission, for instance, is 
usually a congenital affection, arising at a very early 
period of development, while enation takes place from 
structures which are all but complete as to their 
organisation, even though they may not have attained 
their full dimensions. The date of appearance is also 
of consequence in determining the true nature of some 
changes; it does not always follow, for instance, that 
because one organ occupies the position of another, 
it is of the same nature as the one whose place it 
fills. The presence of anthers on petals or on such 
organs as the corona of Narcissus does not necessarily 
constitute those parts actual stamens, but rather 
staminodes. The true stamens are either wanting, or 
if present, they are in advance of their imitators as 
regards their development. 
General morphology of the leaf and axis. Homology. Since 
the time when Goethe’s generalisations were adopted 
by A. P. De Candolle, special attention has been given 
to the form and mode of development of the leaf- 
organ; for as it was well said by Wolff, if once the 
course of evolution and the structure of the leaf were 
