METAMORPHOSIS. 193 



{Galtha palustris) the petaloid stamens occasionally 

 bear marginal ovules. 



Miss D. Gr. Scott has described abnormal flowers of 

 the potato in which some of the stamens, with normal 

 anthers, bore ovules on the filament both on the upper 

 (ventral) surface and in an internal cavity of the 

 filament. 



PI. XL VIII, fig. 2, shows an ovuliferous stamen of 

 the field rose {Rosa arvensis). 



As regards the meaning of the phenomena classed 

 under carpellody, some of them, such as the trans- 

 formation of the stamens of a hermaphrodite flower 

 into carpels, or the formation of ovuliferous stamens, 

 merely show that male and female sporophylls are 

 homologous structures. The appearance of female 

 flowers in a male inflorescence may be regarded as a 

 reversion, and it shows that plants which are now mon- 

 or dioecious had at one time mixed inflorescences. 



The formation of an hermaphrodite flower by 

 transformation of some of the stamens into carpels 

 probably shows that in the past the unisexual flower 

 was derived by the converse process, viz. the change 

 of the carpels into stamens. 



On the other hand the formation of an hermaphro- 

 dite flower by the independent appearance of a pistil 

 within the stamens, probably shows that in this case 

 the unisexual flower arose originally by abortion of 

 the pistil. 



In all such cases it is probable that the organs 

 would be likely to reappear along the same path by 

 which they disappeared. 



(4) GrTNCEOEDM. 



1. Phyllodt. — Phyllody of the carpels is of very 

 frequent occurrence. Different stages thereof may 

 be observed. In some flowers of Primula the styles 

 had merely become green, the carpels being otherwise 

 scarcely changed. In the alsike-clover (TrifoUwm 



VOL, II, 13 



