of Vegetable Embryology. 235 



ing, as I suppose, his opinion on the production of buds on 

 the leaves of Bryophyllum and Malaxis paludosa, concludes 

 that the ovules always spring from the upper surface and 

 margins of a carpel leaf, and that they are wholly unconnected 

 with the axis, which, as he supposes, has no share in the for- 

 mation of the ovarium. Certainly the position of the ovules 

 on the edges of the carpellary leaves in Papaver and others, 

 or at the sides of the midribs in Viola, Sac, would appear to 

 favour these opinions. 



Professor Meyen* believes that the origin of the ovules is 

 fourfold ; that they originate most frequently at the mar- 

 gins of the carpellary leaves ; next, at the sides of the midribs 

 of the carpel leaves ; and lastly, from the axis, where they 

 occur either at the end of the axile formation, or at the side 

 of the frequently much shortened axis. The facts, however, 

 from which these statements are deduced, may be explained 

 upon the supposition that the ovule is an axile formation; 

 and if the ovula be considered as analogous to buds, they 

 will fall in with that very general law — that a bud is never 

 formed on a leaf, but from the axis or its derivative organs 

 alone. The case of Bryophyllum alone offers a real excep- 

 tion to this view. 



MM. Henry and Marquartf have represented the car- 

 pellary leaves separated from the axis and forming stamens, 

 while nevertheless the axile formation produced ovules; 

 than which no better proof can be afforded of the elon- 

 gation of the axis. The most obvious conclusion regard- 

 ing the nature of the true Placenta centrahs hbera is that it 

 is a prolongation of the axis, as in the Polygonece and in 

 Taxus', and Schleiden, who coincides in this view, enume- 

 rates several examples which tend to prove its correctness ; 

 such as the condition of the ovaria of the Fumariaceas and 

 Cruciferae, and of the cones of the Coniferae. Von Martius 

 states that the reproductive organs produce axes of peculiar 



* Report on the Progress of Vegetable Physiology during the year 1837. 

 13y F. J. F. Meyen, M.D. Translated by William Francis. Lond. 1839. 



f Ueber abnorme Bildungen des Fruchtknotens der Salix cinerea, L. mit 

 einer Tafel Abbildungen. Ersten Jahvesbericht des Botanischen Vereines 

 am Mittel- und Niederrhein. Bonn, 1837. 



