454 ON THE. STRUCTURE OF THE FEMALE FLOWER 



point of impregnation, has no organic connection with the 

 parietes of the ovarium, In support of it, also, as far as 

 regards the direct action of the pollen on the ovulum, 

 numerous instances of analogous economy in the animal 

 kingdom may be adduced. 



The similarity of the female flower in Cycadeae and Coni- 

 ferse to the ovulum of other phgenogamous plants, as I have 

 described it, is indeed sufficiently obvious to render the 

 opinion here advanced not altogether improbable. But the 

 656] proof of its correctness must chiefly rest on a resem- 

 blance, in every essential point, being established, between 

 the inner body in the supposed female flower in these 

 tribes, and the nucleus of the ovulum in ordinary struc- 

 tures ; not only in the early stage, but also in the whole 

 series of changes consequent to fecundation. Now, as far 

 as I have yet examined, there is nearly a complete agree- 

 ment in all these respects. I am not entirely satisfied, 

 however, with the observations I have hitherto been able 

 to make on a subject naturally difficult, and to which 

 I have not till lately attended with my present view. 



The facts most likely to be produced as arguments against 

 this view of the structure of Coniferse, are the unequal and 

 apparently secreting surface of the apex of the supposed 

 nucleus in most cases ; its occasional projection beyond 

 the orifice of the outer coat ; its cohesion with that coat 

 by a considerable portion of its surface, and the not unfre- 

 quent division of the orifice of the coat. Yet most of these 

 peculiarities of structure might perhaps be adduced in sup- 

 port of the opinion advanced, being apparent adaptations to 

 the supposed economy. 



There is one fact that will hardly be brought forward as 

 an objection, and which yet seems to me to present a diffi- 

 culty, to this opinion ; namely, the greater simplicity in 

 Cycadese, and in the principal part of Coniferse, of the 

 supposed ovulum which consists of a nucleus and one coat 

 only, compared ynth the organ as generally existing when 

 enclosed in an ovarium. The want of uniformity in 

 this respect may even be stated as another difficulty, for 



