646 DR DICKSON ON DEVELOPMENT OF 



to me, only two suppositions possessing any elements of probability and com- 

 patible with the history of development : either the ovary consists of one carpel, 

 embracing the extremities of the receptacle; or it consists of five connate carpels, 

 as in Primulacese. 



With regard to the first supposition it will, I think, be admitted that it is, 

 a priori, improbable that a corollifloral plant, like Pinguicula, should have only 

 one carpel ; all the orders with which it might possibly be compared having com- 

 pound ovaries. On this ground alone I should be inclined to dismiss the idea. 



On the other hand, the 5-carpellary hypothesis has the support of the mon- 

 strosities just referred to. In some we have the posterior lip of the stigma bipar- 

 tite, in others the anterior lip tripartite.* Now, if we combine these monstrosities, 

 we obtain five parts, and these placed in the proper position — superposed to the 

 petals. Were we to take the ovary of Primula, which originates as an entire 

 annulus, and so modify its development that its anterior part should appear first 

 (just as the anterior part of the calyx in Pinguicula appears first), we should 

 have a structure originating in semilunar form exactly as in the young ovary of 

 Pinguicula. That five connate carpels should go to form a bilabiate stigma, is 

 just what might be expected in a family where the tendency to bilabiation is so 

 strongly marked. To take an extreme case, I may refer to Utricularia minor, 

 where the corolla, with two vascular bundles going to its upper and three to its 

 lower part, is bilabiate with two perfectly entire lips. 



General Conclusions. 



A few words may be said with regard to the probable affinities of the order 

 Lentibulariacese. In the first place, I shall allude to the opinion of Mr Bentham, 

 as quoted by Lindley (Veget. Kingd. p. 686), to the effect that they are very 

 closely related to Scrophulariacene, in " having the same calyx, corolla, stamens, 

 and bivalve capsule, but distinguished solely by their really unilocular fruit, with 

 a free central placenta, and the minuteness of their embryo. In respect of the 

 former character, they come very near to Limosella, Lindernia, and other Gratiolese, 

 with parallel dissepiments and entire valves ; for in these plants the dissepiment 

 is very thin, and usually detaches itself from the valves before maturity, so that 

 beino- concealed by the seeds, which fill nearly the whole capsule, it often escapes 

 observation, and many of these genera have frequently been described as having 

 a unilocular fruit." 



Having, as I think, satisfactorily set aside the idea that the ovary of Lenti- 

 bulariacese is bicarpellary, it is, perhaps, unnecessary on my part to refer to Mr 

 Bentham's view, that the premature detachment from the valves of the thin 



* The variable and inconstant lobules at the base of the middle anterior lobe in this form of 

 monstrosity I am, I think, justified in considering of secondary importance. 



