On the development of the organization in phaenogamous plants / [M.J. Schleiden].
- Matthias Jacob Schleiden
- Date:
- 1838
Licence: Public Domain Mark
Credit: On the development of the organization in phaenogamous plants / [M.J. Schleiden]. Source: Wellcome Collection.
22/40 page 16
![Mirbel was the first who published any detailed account of the general formation of these integuments of the nucleus; but although he has partially observed the phacnomena ac¬ companying their formation, he has evidently been far from understanding them, and could not therefore clearly explain the process ; and it is indeed scarcely possible to collect from his own words what was his real opinion of the matter. We are indebted to R. Brown, who has struck out so many new paths in this and every other department of botany, for the first correct account of their mode of formation in the Orchi- deee in 1831, and at a later date (in 1834) in his dissertation on the female flowers of the Uaffesia*, in which he extended his observations to many other families. Fritsche has how¬ ever furnished the most detailed account of this subject in Wiegmann’s Archiv, but he has confined his observations en¬ tirely to one species, and that the least favourable to such an investigation on account of its compressed growth and ana- tropous ovule. He has also neglected to take accurate mi¬ crometrical measurements, a point of the utmost importance here, by which alone he would have been able to avoid some errors. Thus, for instance, the expansion of a cylinder un¬ derneath a given line, and its contraction above it, are cir¬ cumstances which can only be ascertained in objects so minute by means of comparative measurements, since, of course, every stage of the process cannot undergo examination at the same time, and these differences are of the greatest importance to the true appreciation of the subject. In this manner Fritsche has fallen into the error, on the one hand, of supposing that both integuments are a simultaneous formation produced by the inflexion of the first fold into the body of the ovule, and on the other hand he has viewed the formation of the inner integument in too confined a manner, as a mere fold of the epidermis nuclei. The plan which nature adopts is simply this :—The exam¬ ple I shall select is that of the atropous ovule, for instance of the Polygoneee (fig. 4), as being the most simple. At a certain distance beiow the apex of the original protuberance an ideal line may be recognised, intended as the basis of the nucleus (fig. 4 b.), which does not afterwards increase in thickness. Above this line the apex forms itself into the nucleus, and be¬ low it the substance of the axis expands and forms a protu¬ berance (fig. 4 A), which extending itself as a kind of mem¬ branous fold gradually covers in the nucleus. (Integumentum primum aid internum mihi; Secondine Mirb.; membrana in- [# Account of the results of Mr. Brown’s researches on these subjects will be found in Phil. Mag. and Annals, N. S. vol. x. p. 437, and bond, and Phil. Mag., vol. v. p. 70.—-Edit.]](https://iiif.wellcomecollection.org/image/b30379805_0022.jp2/full/800%2C/0/default.jpg)
