44 THE STRUCTUKE OF FLOWERS. 



to each petal, subsequently dividing into several; for the 

 same pair by repeated tangential division gives rise to the 

 series of stamens (which have been thus doubled) superposed 

 to each petal, both having arisen from a common cord. 



With regard to the numerous carpels of Hollyhock, I 

 find that the axial cylinder which has given rise to the five 

 sepals continues on, and by radial division again supplies 

 cords to the carpels, which are grouped into five sets super- 

 posed to the sepals, as may be easily seen if the pistil be 

 examined from below. Hence, as the sepaline or petaline 

 cords in these flowers each undertake to form a large number 

 of extra parts — many stamens in the one case, and many 

 carpels in the other — it is presumable that neither sepaline 

 stamens nor petaline carpels could be formed. 



With regard to the presence, and consequently the relative 

 position, of one whorl rather than the other of the gynoecium, 

 it is due to the fact that sometimes the sepaline cord will 

 give rise to the dorsal carpellary, as in Althcea and Campa- 

 nula; at others, it is the petaline, as in Fuchsia, Sedum, Ivy, 

 etc. ; so that the carpels become superposed to the sepals or 

 petals accordingly. As instructive instances of variations in 

 this respect occun-ing in the same family, it may be mentioned 

 that all species of Campanula which have five carpels, as also 

 Wahlenbergia capensis, Michauxia, Ganarina, and Lightfootia 

 subulata, have their carpels superposed to the sepals and 

 stamens. On the other hand, Musschia (^Campanula aurea, L.) 

 Platycodon (G. grandiflora, Jacq.), and Microcodon have the 

 carpels superposed to the petals. * 



The fact that either the sepals or the petals can have 

 the carpels superposed to them respectively, just as they can 

 each have a whorl of stamens, and that, in some few orders, 

 the two whorls are actually present, as in Butomece and 

 Jtmcaginece, led me to assume two whorls as the primary 



