82 



PHILOSOPHICAL NOTES OX 



Diagram of the Iris, ^vith the 

 sepals (falls) marked. 



Diagram of a peloric Gladiolus with 

 the petals (standards) marked. 



Transposition of sepals into petals, while the segments are in 

 bud as cellular nipples, will effect the transformation of an Iris 

 into a Gladiolus. 



Form of Gladiolus in which the segment (a) is neither a sepal nor a petal ; 

 half of it belongs to the sepal whorl, and half to the petal whorl. 



Fission. 



This is the opposite of fusion. But if, in the iirst instance, a 

 fusion of two parts had occurred, and then a subsequent splitting 

 up of that fusion, as in the case of the crown of Narcissus 

 telamonius plenus, we would have to deal with what is called a 

 reversion, or a return to some original form. 



Prof. Henslow (" Origin of Floral Structures," Fig. 10) gives 

 an interesting case of a Minmlus flower splitting up into a large 

 numVjer of separate petals, thus reducing it from a monopetalous 

 to a polypetalous flower. The difliculty in such cases is to trace 

 out which was the original, a polypetalous flower, reduced to 

 mouopetaly by fusion, or the reverse. Calystegia 'puhescens^Jlorc 



