CHAP. II. 
OVARY. 
197 
Nevertheless, there are certain stigmas in which no de- 
nuded or secreting surface can be detected. Of this nature 
is that of Tupistra, in which the apparent stigma is a fungous 
mass with a surface of the same nature as that of the style ; 
in such a stigma the mode of fertilisation forms an interesting 
problem, which botanists have yet to solve. 
The centre of a stigma consists of tissue of a peculiar 
character, which communicates directly with the placenta, 
and which is called the conducting tissue. It is more lax than 
that which surrounds it, and serves for the conveyance of the 
fertilising matter of the pollen into the ovules. Schleiden 
well observes that, as a style is a portion of a leaf rolled up, 
or formed by a union of the edges of many leaves (as will be 
presently shown), the centre of the style must answer to the 
epidermis of the upper side of such leaf, and therefore this 
epidermis, modified, constitutes the conducting tissue. If the 
convolution or approximation of the carpels is very complete, 
the tissue will be a mere thread ; but if it be imperfect, as in 
Orchidaceae, &c., the tissue will form the lining of a funnel- 
shaped passage from the stigma to the cavity of the ovary. 
Such is a general view of the more remarkable peculiarities 
of the female system. This part, however, bears so important 
an office in the functions of vegetation, is so valuable as a 
means of scientific arrangement, and is liable to such a great 
variety of modifications, that it will be necessary now to 
regard it in another and more philosophical point of view. For 
we have yet to consider the structure of the compound pistil, 
and to learn to understand the exact nature of its cells, and 
dissepiments, and placentae, and the precise relation that these 
parts bear to each other ; and also to prove that the necessary 
consequence of the laws under which pistils are constructed 
is, that they can be subject to only a particular course of 
modification, within which every form must absolutely, and 
without exception, fall. This enquiry would, perhaps, be less 
important, if none but structure of a very regular and uniform 
kind were to exist ; but, considering the numberless anoma- 
lies that the pistil exhibits, it becomes at once one of the most 
difficult and most essential parts of a student’s investigation. 
o a 
