POSITIVE DRDOTTBLEMENT. 



89 



ance of ancestral characters. These hermaphrodite 

 flowers differed completely from those sometimes ob- 

 served on the male panicle. 



C. Gr. Fraser describes an interesting case of traumatic 

 reversion in Acer Negundo. A branch of a female 

 specimen of this dioecious species had become almost 

 severed from the trunk; as a direct consequence, it 

 would seem, of this wounding, the flowers borne by this 

 branch developed stamens as well as carpels. A 

 remarkable fact was that the characters of the inflo- 

 rescence and calyx, and the number of the stamens, 

 were intermediate between those of the normal male 

 and female flowers of the species. 



In all these cases an increase of floral members is 

 brought about by the reappearance of some which were 

 foi mierly present, but had become suppressed. 



(4) GrYNtECEUM. 



a. Carpels. — Reference has already been made to 

 those tulip-flowers which showed an outer whorl of six, 

 and an inner of three carpels ; in those cases where 

 six carpels are present it is probable that they would 

 have been in two whorls if the vertical space on the 

 floral axis had allowed of it. 



Miss Gibbs describes the presence of a second 

 whorl of carpels as occurring above the normal one 

 in Gerastium qnaternellum. Prain observed the same 

 phenomenon in the rice. 



The character of the navel orange is derived from 

 the fact that an imperfect second whorl of carpels 

 arises above the normal whorl; sometimes a completely- 

 formed second small orange is so developed at the top 

 (fig. 98) or in the inside (fig. 99) of the normal one. 

 These facts show the presence of a floral axis in the 

 centre of the fruit. 



A similar phenomenon occurs occasionally in the 

 tomato ; and Masters gives instances of it in other 

 plants as well. 



