STIGMA IN. LINDENBERGIA. 65 
to his definition, since he quotes Schleidens, observing that 
a style is a portion of a leaf rolled up. Vide Int. p. 197.* 
There can scarcely be much relation between the amount 
of convolution of the parts of the leaf forming the ovary, 
and that forming the style, since large stigmatic canals 
exist in plants, in which the septa are perfect ; and conse- 
quently where no space exists between the margins of the 
leaves, (see Lind. p. 197,) the canal is made to depend 
upon the amount of convolution of the leaves themselves, 
not of their apiculi. 
Probably in these cases the amount depends upon spe- 
ciality of organisation. 
Conclusions. Stigma is the external part of the conducting 
tissue. . 
In many cases it is obviously marginal, and its exterior 
portion a production from the placenta. 
Its modifications are, with or without a superior sinus, with 
or without an anterior sinus, or with none. 
The pistillum is a cuspidate leaf with its margins inimici. 
The ovarium is the lamina ; the style the apiculus; the stig- 
matic surface the exterior part of the conducting tissue, or 
placenta. 
The vessels of the lamina may pass into the style; very 
generally the midrib alone does so, and in all cases when 
only one vessel exists, it is the continuation of the midrib. 
The pistillum may be evascular; in all these cases it is 
never foliaceous, perhaps the greater its vascularity the more 
developed is its green colour. 
Thelamina may be deficient of a midrib, having only 
marginal vessels ; in such cases it occasionally subsequent- 
ly derives a midrib from a recurrent vessel. 
This suggests a question whether, (as no parallel case 
exists in leaves themselves, in which the midrib is in- 
variably the first formed and principal wessel) in such 
instances as Papaver, the midribs do not really bear the 
ovula. But Limnanthes is an undoubted case in point, and 
* Third Ed. Lond. 1839. 
