M. Ad. Brongniart on Vegetable Morphology. 495 



ments of ovules, the papilla corresponding to the nucleus was 

 very small, and entirely exposed upon the slightly concave 

 superior face of the foliaceous lobe. On the lobes whose summit 

 presented a cup-shaped cavity, the nucleus, either little developed 

 or of some size, occupied the bottom of this kind of cup, which 

 corresponded to the primine. In the foliaceous lobes which had 

 more completely taken on the form of ovules, the opening of the 

 cup-like cavity was narrowed, and had altogether the appearance 

 of the micropyle ; the nucleus was more developed, and its free 

 summit corresponded to the opening in the ovulary tegument 

 as in the normal condition. Lastly, the ovule assumed more and 

 more the form and organization of the ordinary ovule of this 

 plant. 



It must be admitted then, that in the plant in question, the 

 vascular bundles of each placenta, or what are often called pistil- 

 lary cords, were formed by the lateral nerves of the carpellary 

 leaf; that each ovule corresponded to a lobe or large tooth of 

 this leaf, and that its funiculus, as well as the raphe as far as the 

 chalaza, was formed by the median nerve of this lateral lobe; 

 that the external tegument, often vascular, of the ovule was nothing 

 but the extremity of this foliaceous lobe folded on itself, forming 

 a sort of hood ; that the nucleus, on the other hand, was a new 

 production, a cellular papilla, developed on the superior face of 

 this lobe of the leaf, and in the cavity which the latter had 

 formed. 



M. Brongniart does not think that it can be contended that 

 these lateral nerves of the carpellary leaves, from which the ovides 

 and toothed lobes were thus indifferently developed, can be re- 

 garded as peculiar processes of the central axis destined exclu- 

 sively to the production of ovules, as many physiologists have 

 contended. 



M. Brongniart believes that this is the general structure in all 

 cases where the placenta is placed on the margin or internal face 

 of the carpellary leaf. 



The author then cites another example of monstrosity which 

 exhibits the same origin of the ovules in a family where the ovary 

 seems, at first sight, to deviate notably from the more ordinary 

 structure of compound ovaries, viz. in the Crucifei'a. In this in- 

 stance, in which all the flowers on a stem of a turnep were ex- 

 amined, some presented the two carpellary leaves composing the 

 siliqua in a normal condition ; others very much developed, and 

 even forming an almost vesicular siliqua, in which the ovules were 

 replaced by little foliaceous expansions, or sometimes the carpels 

 themselves replaced by two free leaves destitute of ovules. 



Some of the vesicular siliquas appeared at first to have the usual 

 organization of the pistil of Cruciferce, although diiFering very 



