NOTES AND MEMORANDA. 51 



tiou of the ovule in Taxus, but I will willingly take it for a terminal 

 leaflet with a monangian sorus equally terminal. 



The carpels of the Angiosperms are distinguished from those of 

 the Gymnosperms in that the former bear the ovules on the superior 

 face, the others on the inferior when the ovules are not exactly 

 marginal. The same observation applies to the stamens, those of the 

 Conifers and the Cycadaceae carry the pollen sacs on the inferior face, 

 those of the Angiosj^erms on the superior face or at the side. 



M. Celakovsky compai'es the stamen of the Angiosperms to the 

 leaf of the Ophioglossum. Assuredly there is here a very ingenious 

 comparison, but one which can only be placed in the category of bold 

 aud somewhat vague hypotheses founded on a too restricted number 

 of observed facts. 



The terminal position of the ovule does not prove that this organ 

 is a bud ; on the contrary, the placentae must be everywhere phyllomes. 



The mode of development of the ovule, especially that of the 

 Conifers, should tend according to some authors to its being considered 

 a bud. It is impossible to have confidence in the history of develop- 

 ment when the question is to determine the morphological nature of 

 an organ. It everywhere requires a correction. M. Strasburger 

 has allowed himself to be too much guided by preconceived ideas 

 in the interpretation of the phenomena of development. Moreover, 

 I have shown that the histogenesis of the ovule, as he has described 

 it, is not correct, especially in relation to the development of the 

 nucleus. 



MM. Celakovsky and Cramer have shown that teratology cannot 

 be invoked to prove that the ovule is a bud. The theory of Brong- 

 niart is much more admissible. In the first place, the carpels and 

 the placentas are phyllomes ; that being so, it is difficult to admit 

 that the ovules are buds. It is true that buds may grow on a leaf, 

 but to admit that the ovules are similar buds developed regularly on 

 a carpellary leaf requires reasons of great weight. Moreover, the 

 descending progression of the integuments is not in accord with this 

 theory. 



Secondly, the teratological cases show us everywhere the ovule 

 (funicle and integuments) transformed into a lobe of a leaf on which 

 the nucleus is a new creation, in the light of an outgrowth : this fact is 

 confirmed by histogenesis. I may recall here that two nuclei have 

 sometimes been observed on the same ovular leaflet, which does not 

 agree with the theory of Braun, but very well with that of Brongniart. 



Thirdly, the development of the nucleus is so like that of the pollen 

 sac of the Angiosperms, that their homology cannot be doubted : 

 further, the pollen sac itself is the homologue of the sporangium ; 

 therefore the nucleus must be compared to the macrosporangium. I 

 do not know why it should be given the name of " sporocyst," which 

 can scarcely be applied to any but the Marattiaceae, for M. Strasburger 

 has not yet demonstrated that the sporangia of the Equisetaceae and 

 the Lycopodiacefe are sporocysts. This name could better be given to 

 the pollen sacs of the Angiosperms. 



The sporangia of the Cryptogams all grow on the leaves. The 



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