224 



No. 6. The central flower ; calyx none ; corolla 5-cleft ; stamens 

 five, petaloid ; ovary of three carpellary leaves ; ovules in six rows. 



" In the tenth flower the centre was occupied by three ovaries and 

 two small flower-buds. One of the ovaries was much compressed, 

 two carpellary leaves open half way, its ovules perfect ; another of 

 the same size and structure enclosed one like itself, the ovules imper- 

 fect." A few other deviations are recorded, and the author continues : 

 " I would particularly allude to the changes which the ovarium and 

 ovules present, and the inferences which may be drawn from these. 

 A simple ovarium is considered to be a modified leaf folded upon it- 

 self, the margins united, and these alone, in most cases, constituting 

 the placenta (necessarily double), and producing ovules. It was at 

 the same time supposed that the stigma was a mere prolongation of 

 the midrib of the carpellary leaf, and, therefore, single and terminal. 

 The greatest botanist of this or any other age, has satisfactorily de- 

 monstrated that each simple pistillum or carpel has necessarily two 

 stigmata, which are to be regarded not as terminal, but lateral ; the 

 style where present being only a mere attenuation, in many cases very 

 gradual, of the whole body of the ovarium. Most Gramineae, many 

 Euphorbiaceae, several Irideae, &c., are stated as illustrating this 

 point. The ovaria, in some of the monstrous flowers already de- 

 scribed, appeared to afford proof of the same, and many carpels in 

 the earlier stages of their development, yield ample evidence that 

 the opinion alluded to is in strict accordance with nature." 



After alluding to observations of Professor Henslow, on the trans- 

 formation of the ovules of mignionette into leaves, and those of M. 

 Brogniart on a monstrosity of Delphinium elatum. Dr. Dickie dis- 

 sents in some degree from the opinions of the last-named botanist. 

 " From careful examination I have been convinced that in some car- 

 pels, whose ovules are numerous, the order of development is from 

 the base to the apex. In very early stages of the carpel, the ovules 

 are confined to the lower part alone, there being no trace of them to- 

 wards the upper part of the placenta. At a more advanced stage they 

 occur throughout a greater portion of its extent, but still there is a very 

 evident difference, previous to impregnation, between the progress 

 made by ovules from the base of a placenta, and those nearer to its 

 apex ; this is obvious to the unassisted eye in regard to the deve- 

 lopment of the membranes, but actual measurement removes all 

 doubt." 



