16 



may also be assumed that the lateral, imperfect, half-obliterated stigmata have 

 a line of placentas, with ovula appertaining to themselves, but so confounded 

 with the placenta? of their lateral and more powerful neighbours, that, in con- 

 sequence of their close approximation, they cannot be distinguished. We, 

 however, incline to the former of these two opinions. Let this be as it may, 

 upon either supposition, the structure of Cruciferous pistilla is, we think, sus- 

 ceptible of explanation. We shall for convenience, reason upon the former of 

 the two hypotheses. 



" If we compare the fruit of Eschscholtzia and Cruciferas, we shall at first, 

 perhaps, be led to believe that while they have a certain degree of resemblance 

 in some points, they nevertheless differ widely in others of more importance : 

 we find both of them with two opposite parietal placenta, connected with a 

 quaternary arrangement of the other parts of the flower, and that in both in- 

 stances their placentae are opposite to stigmata. But we also see that in Cru- 

 ciferae dehiscence takes place by the separation of two valves from the sides of 

 the siliqua, leaving the placentas undivided ; while in Eschscholtzia it takes 

 place through each placenta, half of which, therefore, adheres to each edge of 

 the two valves into which the fruit finally separates. But if we look into their 

 structure a little more narrowly, we shall perhaps find that these differences 

 are not only capable of reconciliation, but that they explain each other. 



" The fruit of Cruciferas is separable into four parts ; that is to say, into two 

 valves without stigmata, and two double placentas without valves : in Esch- 

 scholtzia there are two valves with placenta? and stigmata, and two stigmata 

 without valves or placentas. But suppose that the two valves of Cruciferas had 

 stigmata, as they should have (and a tendency to produce which actually ex- 

 ists in Iberis umbellata), and that the two stigmata of Eschscholtzia had valves, 

 as would be regular, what would then be the difference between the two 1 It 

 would be reduced to nearly this : that in Eschscholtzia the two placentiferous 

 pieces would occupy the greater part of the pericarpium, the two sterile valves 

 being very small ; while in Cruciferas the two placentiferous pieces would be 

 very small, the chief part of the pericarpium being occupied by the sterile 

 valves." 



Such was the idea I was led, by the curious structure of Eschscholtzia, to 

 entertain in 1828, upon the fruit of Cruciferas. I am aware that it is possible 

 to explain the peculiar economy of the replum of Cruciferas by that of Carmi- 

 chaelia, and that the line of dehiscence in fruit is no evidence of the plan upon 

 which it has been constructed. I also know that a less paradoxical way of 

 understanding the structure of the Siliqua, is to take two confluent carpella, 

 each of which has a 2-lobed or 2-horned stigma, for the type of such a fruit ; 

 upon which supposition each apparent stigma of the siliqua will be made up of 

 two halves : and moreover I have been shown by Mr. Brown some instances 

 of monstrous formation, which seem to confirm such an opinion. Neverthe- 

 less, I wish to record, in this book, my view of the subject, whether it shall be 

 ultimately found to be accurate or inaccurate, for the following reasons. In 

 the first place, it will show young botanists how narrowly it is necessary for 

 them to observe the structure of plants, and how indispensable it is to bear 

 constantly in mind the analogies that exist between the formation of one plant 

 and another ; in the second place, by pursuing the discussion, I hope to induce 

 some one to set the question at rest, by means of such demonstration as it is 

 capable of receiving ; and thirdly, I still retain my opinion, notwithstanding 

 what I have seen and heard since it was formed ; relying chiefly upon the pe- 

 cubarities of Eschscholtzia, which seems to me to be so intimtely connected 

 with the question at issue, and so obviously formed upon the same plan as 

 Cruciferas, whatever that plan may be, that what can be shown to be true of 

 one must be true of the other. 



