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 270 OBSERVATIONS ON PLANTS

218] formed of two lamellae^ derived from the parietes of the fruit. These lamellse are in many cases easily separable,

before the Liuneaii Society in February, 1816, and printed in the twelfth volume of their 'Transactions,' published in 1818. In this volume (p. 89), I observe that " I consider the pistillum of all phfenogamous plants to be formed on the same plan, of which a polyspermous legumen, or foUiculus, 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. 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 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 placentae, each of these being made up of two confluent chordulse, belonging to different parts of the com- pound organ."

In endeavouring to support this hypothesis by referring to certain natural families, in w^hich 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 c-ccurring in Goodenovire, 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 placenfse, 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 13occonia, in the original species of which {B. fj'utesccns)^ the insertion, of the single erect ovulum has the same relation to its parietal placcntfe, as that of Compositee has to its filiform cords, a second species {B. cordafa) exists, in which these placentaj are poly- spermous."

From 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 Cruciferse, which has since been proposed, but without reference to that essay, by M. De Candolle, in the second volume of his ' Systenia Naturale ;' 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, who 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 {S,i/st. Nat. 2, p. 89) ; nor the latter that they were all polyspermous. {Mirbel in Ami. des Scien. Nat. 6, p. 2G7). lle- specting Bocconia cordata., though it is so closely allied to Bocconia as to afford an excellent argument in favour of the hypothesis in question, it is still suSieiently different, especially in its polyspermous ovarium, to constitute a distinct genus, to which I have given the name (Macleaya corda(a) 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 known.

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