24 THE STRUCTURE OF FLOWERS. 



these latter which by lateral or radial " chorisis " supply the 

 cords required for the stamens and carpels 



The consequence is that the essential organs have their 

 cords issuing from a common stem with those of the perianth. 

 Thus they are compelled to stand superposed to them. 



Perhaps the word " compelled " requires a woi'd of ex- 

 planation. The cord of any organ superposed to another 

 may be given off either by radial, i.e. lateral, or tangential 

 chorisis from the cord of the latter. Instead, however, of 

 the new lateral branch giving rise to an organ by the side of . 

 the former, it results, partly from the close proximity of the 

 two and partly from the tendency of the remaining cords of 

 the cylinder to " close up," that the new member finally 

 takes up a position in front of, i.e. superposed to, the one 

 whose cord has given rise to it. When a cord is separated 

 by tangential chorisis, as is so often the case with staminal 

 cords, then the resulting organ must necessarily be super- 

 posed to the one, from the cord of which it has been 

 detached. 



