830 



to arise more or less distinctly from the posterior side of the ovary, 

 and that the same circumstance occurs, although less distinctly, in 

 Centaurea nigra. In such Cichoraceae as he has examined, he has 

 found the raphe for the most part or always lateral ; but as he regards 

 the carpella of this division of Compositae as being right and left of 

 the axis, he concludes that the position of the ovule might be ex- 

 pected to be different. The position of the raphe in Berberis vulga- 

 ris is occasionally next the placenta, but more frequently tends to be 

 averse to it. 



5. The character of ovule erect, with the raphe lateral (first 

 observed by Mr. Bennett in Rharaneae, and by him attributed to a 

 torsion of the funiculus), obtains to a considerable extent among Ex- 

 ogenous families. It occurs regularly in Stilbe pinastra, and gene- 

 rally in one-seeded fruits of Berberis vulgaris ; but in two-seeded fruits 

 of the latter the raphe is removed from the placenta and placed nearer 

 to the dorsal rib of the ovary. In Vitis, on the contrary, whether 

 with one- or two-seeded cells, the raphe is always next the placenta. 

 In a species of Justicia, with two ovules, placed one above the other 

 and quite erect, the raphe is lateral ; but in Mendozia, with a similar 

 placentation, it is apparently next the axis. As other instances of 

 lateral raphe with erect ovules Mr. Clarke cites Elaeagnus orientalis, 

 Calamus viminalis, and Trianthema decandra, the direction of the 

 curvature in the embryo of the latter being regarded as analogous to 

 the position of the raphe in the two former. 



6, The position of the raphe next the placenta is well known to be 

 the ordinary condition in erect anatropal ovles, and on this head the 

 author enters into no details. 



Mr. Clarke then proceeds to consider the causes by which these 

 differences in the position of the raphe may be produced. 



1. He adopts the opinion (first demonstrated by Mr. Brown) that a 

 single ovule pendulous with raphe aversa is the result of an erect 

 ovule pressed or growing downwards from the elongation of the 

 cavity of the ovarium in that direction, while its upper part remains 

 stationary ; but suggests that it is only when an erect ovule has the 

 raphe properly next the placenta that it has raphe aversa, when it 

 thus becomes pendulous. And looking to their affinities, he thinks 

 it not improbable that all pendulous orthotropal ovules should be 

 referred to the same cause. 



2. He believes that a single pendulous ovule with the raphe lateral 

 is an ovule originally extending horizontally from the placenta with 



