M. Ad. Brongniart on Vegetable Morphologij. 497 



the foliaceous appearance and became completely free^ the lobes 

 which replaced the ovule disappeared, and the two leaves in most 

 flowers were oval and quite entire, but marked with three very 

 distinct longitudinal nerves, the borders retaining no trace of 

 the pinnatifid form, which they only appeared to present when 

 they took the character of placentae. 



It is also remarkable, that in the pistils thus become completely 

 foliaceous, there were again found the little axillary branches and 

 the prolongation of the principal axis, bearing at its summit, but 

 at some distance from the insertion of the carpellary leaves, either 

 a bud composed of small leaves, the external of which formed a 

 cross with the carpels, or else little abortive flower-buds. 



Thus in this plant with carpels intimately united, we find that 

 the ovules are also a dependence and a result of the modification 

 of the margins of the leaf analogous to what w^e have seen taking 

 place in the carpels oi Delj)hiniwn. It is impossible to consider the 

 placenta as a dependence of the principal or secondary axes, since 

 we find these developed under the form of little branchlets, and 

 existing at the same time as the placentse. 



There only remain then the pistils with a free central placenta, 

 which appear difficult to reduce to the same type, that is, to car- 

 pellary leaves with marginal placentation ; but with respect to 

 these it must be remarked, that their pistils are formed after two 

 very distinct types, that of the Caryophyllece and allied families, 

 and that of the PrimulacecE and their analogues. There, even, 

 the occurrence of monstrosities comes to confii-ni the differences 

 which the normal structm-e indicates in the composition of these 

 pistils. 



Thus the pistil of CaryophyllecB presents in many cases parti- 

 tions which perish or disappear at a more or less advanced epoch 

 of their development, and the placentse appear to occupy, as in 

 ordinary multilocular pistils, the margins of the carpellary leaves 

 brought together and soldered round the ideal axis of the flower. 

 An instance of monstrosity of one of the Silenea (M, Brongniart 

 believes a Saponaria), communicated by M. Bravais, confirms this 

 supposition, for the carpels had become partly free and open, and 

 bore ovules on their margins. 



On the other hand, in the Primulacea there are never any 

 traces of partitions ; the ovules are fixed upon an almost globular 

 placenta, not divisible into longitudinal bundles, and in the fre- 

 quent instances of monstrosities observed in Primula, Anagallis, 

 Cortusa, Lysimachia, &c., the pistil has never been seen to change 

 into ovuHferous carpellary leaves ; but, on the contrary, the cen- 

 tral placental axis, elongated in the form of a central column, bears 

 ovules more or less mollified, which pass into the state of as many 

 little distinct leaves as there are ovules. 



