156 Mr. D. Don oji the Origin and Nature 



edges is occupied by a fascicle of vessels : the two parallel ones, 

 which are also generally the most prominent, develop them- 

 selves into the ligulate appendage ; and the third, which occu- 

 pies the facial edge, terminates abruptly in the sinus. There are 

 other vessels which occupy the space between the three prin- 

 cipal trunks. These circumstances taken together, have induced 

 me to regard the corolla as wanting in the rays of Zinnia. 



My own observations tend fully to confirm the interesting 

 hypothesis advanced by Mr. Brown respecting the compound 

 nature of the pistillum in Compositce. In Zinnia verticillata and 

 multijlora the branches of the style, especially of such flowers as 

 have an increased number, only partially cohere together, are 

 readily separable, and may be traced from the apex of the 

 stigmata to their connexion with the two filiform cords to which 

 the embryo is attached, and which Mr. Brown* regards as a 

 species of placenta. These cords, which are particularly distinct 

 in Zinnia, are slightly thickened at their extremity, and bear a 

 striking analogy to the slender bases of the filaments, which are 

 generally found adherent to the tube of the corolla, as the former 

 are to the sides of the ovarium. The embryo is attached to the 

 inner edge of the extremities of these cords, one of which I have 

 frequently found not adhering to the parietes of the ovarium, but 

 passing down its centre quite free. In some cases the branches 

 of the style are found wholly free, so that they resemble so many 

 distinct stjdes ; and they may not unaptly be compared to those 

 of Umbelliferce and Araliacece. The embryo of Zinnia is easily 

 extracted from the ovarium entire suspended between the two 

 placental cords, and surmounted by the style and stigmata ; and 

 as there appears to be no interruption between the branches of 

 the style and these cords, it occurred to me as probable that they 

 would prove only a continuation of that organ. 



* Litm. Tram. vol. xii. p. 89- 



The 



