238 Miscellaneous. 



was taken into consideration, and a great dilution of the solutions 

 assumed, because otherwise the petrifaction would be prevented and 

 incrustations produced ; and at the same time reference was made to 

 the remarkable and hardly explicable phsenomenon, that with all the 

 similaritjf of the processes of a former world with those of the pre- 

 sent one, and notwithstanding the petrifactions by lime and oxide of 

 iron now observed, still no siliceous petrifactions have been discovered, 

 although in living ])lants, or at least in particular parts of them, 

 silicifications take place in a comparatively very short time, and in- 

 deed in tlie same way as formerly in fossil woods, as in the epidermis 

 of the stem of the Equiseta, in the Bamboos, the seeds of many 

 Grasses, and above all, in the exceedingly remarkable tree called 

 El Cauto, discovered by Kriiger in Trinidad, in which, after the cells 

 are filled, even the organic walls at last disappear, and become re- 

 placed by silica. All this, and many other circumstances are in 

 favour of the former existence of conditions which have hitherto 

 escaped our observation. — Abstract of a monoir read before the 

 Silesian Society, Nov. 27, 1857. 



Structure and Development of the Flower and Fruit of the Pear, 

 By J. Decaisne. 



From a communication made to that active association, the Bo- 

 tanical Society of France, we learn that Decaisne has proved, by 

 direct observation of the development, the correctness of that 

 view respecting the structure of the pomaceous fruit which we 

 have always maintained on general morphological grounds. The 

 pips are the true pistils ; they are separate and free at their first 

 appearance ; a little later, a growth from the receptacle forms an 

 open cup around them, ends by completely investing them, and 

 becomes the flesh of the core. In the Pear, as the base of the at 

 first sessile flower-bud elongates into a peduncle, the upper part of 

 this thickens with the bud itself, and forms the tapering lower part 

 of the Pear, which therefore below the carpels is formed of the stalk, 

 as absolutely as in Anacardium or Hovenia. From these observa- 

 tions, and others upon Melastomacece, &c., Decaisne concludes that 

 the orthodox view of the structure of the flower, " as explained by 

 our illustrious masters, R. Brown, De Candolle, and Jussieu," is de- 

 monstrably correct ; tliat " it is not necessary to call into account 

 that axis which is at the present day so often and so willingly ap- 

 pealed to for explaining the structure of flowers and fruits ;" that 

 " it is not impossible to bring under the common law of organization 

 the ovaries with a free central placenta, whose differences from ordi- 

 nary ovaries are more apparent than real;" and that most probably 

 placentation always, in spite of appearances, belongs to the ovarian 

 leaves. We are pleased to find that the experience of this eminent 

 botanist has brought him into agreement, as regards the conception 

 of species, with the views of those whom we must regard as the 

 soundest workers and writers of the present day, and those on whom 

 the hopes of the science rest. He states that if he had the P/««- 



