90 Mr. Brown's Observations on the 



that of the parts of the calyx or corolla, enters into my notion of 

 a flower complete in all its parts. 



But from this type and number of pistilla many deviations take 

 place, arising either from the abstraction of part of the complete 

 series of organs, from their confluence, or from both these causes 

 united ; with consequent abortions and obliterations of parts in 

 almost every degree. According to this hypothesis, the ovarium of 

 a syngenesious plant is composed of two confluent ovaria; a struc- 

 ture which is in some degree indicated externally by the division 

 of the style, and internally by the two cords which I consider as 

 occupying the place of two parietal placentae, each of these being 

 made up of two confluent chordulae, belonging to different parts 

 of the compound organ. I am well aware how very paradoxical 

 such an hypothesis must seem, especially when applied to a struc- 

 ture apparently so simple as that of the ovarium of Compo- 

 sitae ; and I therefore regret that I am not yet fully prepared 

 to bring forward in its support a series of facts already in my pos- 

 session, consisting of deviations from the usual structure of organs, 

 and particularly of instances of stamina changed into pistilla. 



In the mean time it may give some plausibility to the hypo- 

 thesis to remark, that there are families of plants strictly natural 

 in which a series of degradations exist, if I may so speak, from 

 the assumed perfect pistillum, to a structure as simple as that of 

 Compositae. 



Thus in Proteacece we have the type of the perfect pistillum in 

 the many-seeded foUiculus of Embothrium ; the first degree of im- 

 perfection in that of Gremllea, where only one ovulum of each 

 series remains; a further reduction in the indehiscent mono- 

 spermous fruit of Leucospermum, in which the insertion of the 

 ovuJum is lateral ; and the simplest form in Protea itself, where 



the 



