558 ON THE RELATIVE POSITION OF 



These are the piiiicipal luodificalions of the coiiipouncl 

 ovarium when forming a simple series ; bnt it is necessary 

 to observe that both smfaces of the infiectecl and included 

 portions of the carpels are not unfrequently equally pro- 

 ductive of ovula, a structure whicli is manifest in numy 

 Cf/rtandracece, especially Cyriaiulra, although in several 

 other genera of the same family the production is confined 

 to the inner or upper surface of the margin. In other cases 

 the polyspermous ovuliferous portion or placenta is connected 

 with the inner angle of the cell by a single point only, wliich 

 may proceed either from the apex or base of the cavity. 

 This modification of structure, though in some families 

 hardly of generic importance, seems to me to assist in 

 explaining the apparently anomalous structures of Hydnora, 

 liafflesia, and Brugmaima. 



On the subject of the origin and type of Stigma, my first 

 observation is, that the style where present can only be 

 regarded as a mere attenuation, in many cases very gradual, 

 of the whole body of the ovarium. Hence the idea natu- 

 rally suggests itself, that the inner margins of the carpel, 

 which in the lower part are generally ovuliferous, in the 

 upper part perform the different, though in some degree 

 analogous, function of stigma. As the function, however, 

 of this organ implies its being external, and as in different 

 famihes, genera, and even species, it has to adapt itself to 

 nrr various arrangements of parts destined to act upon it, 

 corresponding modifications of form and position become 

 necessary ; hence it is frequently confined to the apex, and 

 very often, es[)ecially in the compound ovarium with united 

 styles, appears to be absolutely terminal. 



In such cases, as it must always include and be closely 

 approxinjated to the vascular cord of the axis, it has by some 

 botanists been considered as actually derived from it, which 

 it is, liowever, only in the same manner as the marginal pla- 

 centae are derived from the axis of the carpel. But according 

 to the notion now advanced, each simple pistillum or carpel 

 has necessarily two stigmata, which are to be regarded, not 

 as terminal, but lateral. 



That the stigma is always lateral may be inferred from its 



