270 OBSERVATIONS ON PLANTS 



218] formed of two lamellse^. derived from the parietes of the 

 fruit. These lamellee are in many cases easily separable, 



before the Linnean Society iu February, 1816, and printed in the twelfth volume 

 of their 'Transactions,' pubUshed in 1818. In this volume (p. 89), I observe 

 that " I consider the pistillum of all phsenogamous plants to be formed on the 

 same plan, of which a polyspermous legumen, or folliculus, whose seeds are 

 disposed in a double series, may be taken as the type. A circular series of 

 these pistilla disposed round an imaginary axis, and whose number corresponds 

 with that of the calyx or corolla, enters into my notion of a flower complete in 

 all its parts. Bat 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 conse- 

 quent 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 structure in some degree indicated externally by the division 

 of the style, and internally by the two cords (previously described), which I 

 consider as occupying the place of two parietal piacentee, each of these being 

 made up of two confluent chordulae, belonging to different parts of the com- 

 pound organ." 



In endeavouring to support this hypothesis by referring to certain natural 

 families, in which degradations, as I have termed them, are found, from the 

 assumed perfect pistillum to a structure equally simple with that of Compositse, 

 and after noticing those occurring in Goodenoviee, I add, "The natural order 

 Cruciferse exhibits also obliterations more obviously analogous to those assumed 

 as taking place in syngenesious plants ; namely, from a bilocular ovarium with 

 two polyspermous parietal placentse, which is the usual structure of the order, 

 to that of Isatis, where a single ovulum is pendulous from the apex of the 

 unilocular ovarium; and, lastly, in the genus JJocconia, in the original species 

 of which {B. /rutescens), the insertion of the single erect ovulum has the same 

 relation to its parietal placentK, as that of Compositte has to its filiform cords, 

 a second species (B. cordata] exists, in which these placentse are poly- 

 spermous." 



Trom this quotation it is, I think, evident, that in 1818 I had published, in 

 my essay on Compositte, the same opinion, relative to the structure of the 

 pistillum of Cruciferae, which has since been proposed, but without reference 

 to that essay, by M. De Candolle, in the second volume of his ' Systema 

 Nalurale ;' and I am not aware that when the essay referred to appeared, a 

 similar opinion had been advanced by M. De Candolle himself, or by any other 

 author ; either directly stated of this family in particular, or deducible from 

 any general theory of the type or formation of the pistillum. I am persuaded, 

 however, that neither M. De Candolle, when he published his ' Systema.'nor M. 

 Mirbel, wlio has very recently adverted to this subject, could have been ac- 

 quainted with the passage above quoted. This, indeed, admits of a kind of 

 proof; for if they had been aware of the concluding part of the quotation, the 

 former author would probably not have supposed that all the species referred 

 to Bocconia were monospermous (Sj/sL Nat. 2, p. 89) ; nor the latter that 

 they were all polyspermous. {Mirbel in Ann. des Scien. Nat. 6, p. 207). Re- 

 specting Bocconia cordata., though it is so closely allied to Bocconia as to afi'ord 

 an excellent argument in favour of the hypotliesis in question, it is still 

 sufficiently different, especially in its polyspermous ovarium, to constitute a 

 distinct genus, to which I have given the name (Macleaya cordata) of my 

 much valued friend Alexander Macleay, Esq., Secretary to the Colony of New 

 South Wales, whose merits as a general naturalist, a profound entomologist) 

 and a practical botanist, are well knowji. 



