BEOULAB PELOBU. 225 



corolla. Arum inaculatum has likewise been met with 

 provided with a genuine perianth as in Acoms and 

 other Orontiads. The unusual development of the 

 sexual organs in dicHnous flowers has been alluded to 

 under the head of heterogamy, and other cases where 

 the sjTnmetry of the flower is rendered regular, by the 

 development of parts ordinarily suppressed, will be 

 found in the chapters relating to de\aations from the 

 usual number of organs. 



This change, or rather this persistence of a form that 

 is usually transient, is generally accompanied by some 

 other alterations. Change of direction, as has been 

 already mentioned, is one of the most common of 

 these; separation of the petals {Antirrhmum, Verhascinn, 

 &c.), and even their appearance in leaf-like guise, are not 

 infrequent [Delphinium, Antirrhinum, Verbascum, &c.) 

 At other times multiplication or increased number of the 

 whorls of petals takes place, often, but not always, at the 

 expense of the sexual organs of the flower. Perhaps 

 even more frequent is the increased number of parts 

 in the same whorl in cases of regular peloria ; thus, in the 

 Pelargoniums before alluded to, the parts of the flower 

 are frequently regulated by the number six instead 

 of five. 



This form of peloria is most generally met with in 

 flowers that are placed at the end or in the centre of 

 the inflorescence, or in such flowers as occur singly at 

 the end of the flower-stalk, as in Twpceolum, Viola, &c. 

 It would hence seem as if the freedom from pressure 

 or restriction on one side allowed the flower to develop 

 equally in all directions, and thus to produce regularity 

 of form. 



It is obvious, from what has been before said, that 

 the process of fertilisation is in many cases interfered 

 with and altered by the change in the conformation 

 of the flower. 



From overlooking the occasional existence of this 

 form of peloria, new genera have sometimes been 

 formed on insufficient grounds. The genus Aceran- 



15 



