355 a BRASSICACEiE. [Cistales. 



For further remarks upon the theory of Cruciferous structure, see Moquin Tandon, 

 and Barker Webb in the Mem. Acad. Toulouse. These authors consider the flower as 

 possessing a regular quaternary structure, the fruit itself being composed of 4 

 carpels ; but they do not regard the horns of Parolinia, Fig. CCXLIV., as anything 

 more than horn-like processes of the back of the carpels. The substance of their 

 theory is as follows. " The examination of the structure of the fruit in Escholtzia 

 californica induced Dr. Lindley to create an entirely new theory, to explain the 

 position of the stigma and placentae. — Bot. Reg., Vol. XIV. 1828, fol. 1168. He 

 imagines that the intervals which separate the two placenta} form each a carpellary leaf, 

 reduced to its smallest dimensions and surmounted by its stigma ; and that the two 

 greater valves represent two other carpels exceedingly developed, whose stigmas and 

 placenta? are abortive. This very ingenious theory, which, though not true, presents 

 a mosi seductive appearance of reality, has been generally accepted. Professor 

 Kunth admitted and illustrated it with figures, adding a view of his own as 

 to the nature of the dissepiment. This opinion by no means agrees with the 

 observations on Embryogeny published by Trecul. — Ann. des Sc. Nat., 2-ieme Ser , 

 Vol. XX. p. 339. 



" Having explained the opinions of those who have gone before us, let us develop 

 our own. The carpellary leaf (phyllidium) and its result, the carpel in reality, 

 differ in appearance only from that of other polycarpous plants. Both reasoning and 

 analogy have brought us to this conclusion ; and its truth is confirmed by the 

 monstrous flowers published by different authors. 



"As in other carpellary leaves, the ovuliferous nerves, or placenta?, are carried 

 along the border of the leaf, and are modifications, in fact, of its lateral nerves. At 

 their summit they form a two-headed stigma, whose two heads are separated by the 

 depression resulting from the non-development of the middle nerve of the leaf. The 

 two or more carpellary leaves which compose the ovaiy are exactly united by their 

 placenta? and stigmata ; and the apparent stigma derived from their union is divided 

 by the common canal resulting from the depression of both carpellary leaves con- 

 founded together. The lateral lobes of each opposite carpellary leaf being thus 

 brought together and forming an apparent whole, botanists supposed they had before 

 them two stigmas in this order opposed to the placenta?, which was contrary to all 

 analogy. 



" When the fruit is ripe, the placenta? and stigmas of the two united carpels remain 

 attached to each other, as well as the double spurious dissepiment,* which they have 

 projected to the middle of the fruit, or, in the fenestrate genera, to within a short 

 distance of the axis, whilst the lamina? of the leaves, transformed into valves, fall off. 

 In the Parolinia ornata the summit of the carpel is protruded in the form of two 

 naiTow horns almost parallel, bifurcated at their extremity, much longer than the 

 styles, but so like styles, that Dr. Lindley in his elaborate work (Veg. Kingd. p. 352.) 

 has mistaken them for these. They are mere prolongations of the valves whereof 

 they form part, and with which they fall off when the fruit is ripe, leaving the true 

 stigmata attached to the placenta?. A similar dehiscence is seen in Papaveracea? and 

 several Capparids. In the genus Tetracellion, where the capsule has assumed the 

 normal tetramerous type, the fruit is nearly that of a Poppy, the chief difference 

 consisting in the spurious dissepiments, which in this curious genus do not reach the 

 axis. The dehiscence of Tetracellion is precisely the same as that of Argemone 

 mexicana. The stigma is depressed in the middle, and it is not difficult to detach 

 the carpellary leaves, so that each is surmounted by the portion of the collective 

 stigma which belongs to it. One of us has found flowers of Iberis with 4 sepals, 

 4 petals, 4 stamens, and 3 or 4 carpels, the first in Diplotaxis tenuifolia, the second 

 in Lepidium sativum and Cheiranthus Cheiri. — Monstr. Veg. p. IB and 14, and 15, 

 Jig. 8, and following. 



" Another analogy confirms our opinion. On examining the gynceceum of 

 Escholtzia californica, which has four stigmas, we find that each pair surmounts a 

 carpellary leaf ; if we imagine each separate stigma of each pair to be united with its 

 neighbour of the opposite pair, we obtain the two spurious stigmas of the greater 

 part of Crucifers. 



"If we call Teratology to our aid, we find that in all cases, where through 

 monstrosity the pistil becomes foliaceous, the ovules are placed at the margin of the 

 leaf; and if the stigma is formed, it is dicephalous and placed at the summit. — See 



* M. Trdcul has shown that the dissepiment, originally simple, becomes double by the rupture 

 lengthwise of the lax and elongated tissue of the interior cells. 



