Stigma and Parietal Placenta in Plants. 41 



adopted by Mr. Lindley, namely, that it consists of six car- 

 pels, of which three, placed opposite to the outer series of pe- 

 rianthium or sepals, are sterile ; the remaining three, opposite 

 to the inner series, or petals, being fertile, and bearing their 

 placentae on their axes or discs. 



The chief argument in support of this view is no doubt de- 

 rived from the very remarkable dehiscence of the capsule into 

 six valves. But I have elsewhere pointed out cases where an 

 analogous dehiscence occurs, in which, however, a similar 

 composition has never been supposed to exist : and if the pre- 

 sence of six vascular cords in sections of the ovarium be like- 

 wise adduced in favour of the opinion, 1 may add that I have 

 in the same place remarked that these vascular bundles be- 

 long not to the ovarium only, but also to the perianthium and 

 stamina, and are equally observable in other families with ad- 

 herent ovarium, as Irideee, in which a similar composition has 

 never been inferred. 



With regard to the second family, in which Mr. Lindley 

 believes the disc of the carpel to be ovuliferous. namely, Oro- 

 banchece, I find no other argument advanced in support of this 

 view than that derived from the bursting of the capsule into 

 two lateral valves : but an opinion founded on dehiscence only 

 may be said to be a mere begging of the question ; division 

 through the axis of carpels, especially in the families related 

 to OrobanchecB, being nearly as common as separation of their 

 margins. In this family also, as in Orchide<s, the placentee 

 are double, an argument in favour of their submarginal origin : 

 and although, whether the carpels be regarded as lateral, or 

 anterior and posterior, the placentae are not strictly marginal, 

 yet there are other families where a similar position of pla- 

 centae is found, but in which the structure assumed in this 

 hypothesis has never been suspected. As to the supposed 

 affinity of Orobancheoi with GentianecB, which might be ad- 

 duced in support of this view, as far as it is founded on the 

 assumed agreement of the two orders in the lateral position of 

 their carpels, the argument, even if correct, would hardly be 

 conclusive ; for in Gefitianece there is at least one genus ha- 

 ving quadrifid and another with quinquefid flowers, in which 

 the carpels are not lateral, but anterior and posterior, as I be- 

 lieve them to be in Orobancheae ; nor has it ever been supposed 

 that in GentianecB the disc or axis is ovuliferous. 



In the account now given of the modifications of ovarium 

 and stigma, I have, in conformity with the ordinary language 

 of botanists, employed the term confluence, by which, how- 

 ever, is not to be understood the union or cohesion of parts 

 originally distinct, for in the great majority of cases the sepa- 



