52 THIRD REPORT — 1833. 



of Du Petit Thouars was susceptible of demonstration ; it was 

 more distinctly shown by the interesting discovery of Professor 

 Henslow, that the leaves of Malaxis pahidosa had on their 

 margins what no doubt must be considered buds, but what in 

 structure are an intermediate state between buds and ovula ; 

 and it has been recently asserted by Engelmann*, still, how- 

 ever, without the production of any proof, that "ovula are buds 

 of.a higlier kind, their integuments leaves, and their funiculus 

 the axis, all which, in cases of retrograde metamorphosis, are in 

 fact converted into stem and gi'een leaves." The nearest ap- 

 proach to a demonstration that has yet been afforded of ovula 

 being buds is in a valuable paper by Professor Henslow, just 

 printed in the Transactions of the Philosophical Society of Cam- 

 bridge]-, in which it is shown that in the Mignonette the ovula 

 are in fact transformed occasionally into leaves, either solitary 

 or rolled together round an axis, of which the nucleus is the 

 termination. 



M. Dumortier has endeavoured to prove:}: that the embryo 

 itself is essentially the same as a single internodium of the stem 

 with its vital point or rudimentary bud attached to it. Although 

 the author's demonstration is a failure, and his paper a series 

 of confused and illogical reasoning, yet there can be little doubt 

 that the hypothesis itself is a close approximation to the truth. 



Dr. George Engelmann has recently attempted § to classify 

 the aberrations from normal structure, which throw so much 

 light upon the real origin and nature of the organs of plants. 

 He has collected a very considerable number of cases under 

 the following heads. 1 . Retrograde metamorphosis (Regressns), 

 when organs assume the state of some of those on the outside 

 of them, as when carpella change to stamens or petals, hypo- 

 gynous scales to stamens, stamens to petals or sepals, sepals to 

 ordinary leaves, irregular structure to regular, and the like. 



2. Foliaceous metamorphosis {Virescentia), when all the parts 

 of a flower assume more or less completely the state of leaves. 



3. Disunion {Disjiinctio), when the parts that usually cohere 

 are separated, as the carpella of a syncarpous pistillum, the 

 filaments of monadelphous stamens, the petals of a monopeta- 

 lous corolla, &c. 4. Dislocation {Apostasis) ; in this case the 

 whorls of the flower are broken up by the extension of the 

 axis. 5. Viviparousness {Diaphysis), when the axis is not only 

 elongated, but continues to grow and form new parts, as in those 



* De Antholysi Prodrnmus, p. 61. j vol. v. Part I. 



X Nova Arta Academiw Naturrp Curiosorum, vol. xvi. p. 215. 

 § De Antholysi Prodromus. 



