130 Meyen's Report for 1839 on Physiological Botany, XVIII. — Report of the Results of Researches in Physiological Botany made in the year 1839. By F. J. Meyen, M.D., Professor of Botany in the University of Berlin*. [Continued from p. 35.] Anatomy of Vegetables, M. DECAiSNEf has published a short notice on the structure of the wood of the Misseltoe : he could not confirm the state-ment of M. Dutrochet, who says that the woody body is wanting in the articulation (Gliederung) between the inter-nodes, and is only connected by a cellular layer of pith, so that, properly speaking, the internodes are connected together solely by the bark. According to M. Decaisne r s observations, it is exactly in the internodes that the vessels of the bark are separated ; and he says, that on this fact the articulation of this plant depends, but not on the separation of the fibres of the wood. The wood of Viscum exhibits no vessels (hereby is meant simple spiral tubes. — Mey.), and only in the pith were seen annular tubes ; the nerves of the leaves did not possess any spirals. The number of the vascular bundles (Holzbiindel) in young twigs is regularly eight, seldom seven or nine, and each is surrounded, both inwardly and out-wardly, with a bundle of bast cells. M. Dutrochetf attempted to demonstrate to the Academy that his former statements were correct. Already in 1838 M. Morren§ had made some physiological observations on a new plant named by him Malaxis Par thorn, which, however, I have only lately seen. M. Morren indicates, that a colouring matter similar to indigo must be contained in the leaves of this plant, as in the flowers of Calanthe vera-trifolia and in the leaves of Mercurialis perennis, &c. The presence of indigo in the Orchidea was however discovered years ago by M. Marquart in Bonn. The air-rootlets which were examined by M. Morren Were covered with a quantity of very fine hairs, consisting of single transparent cells, the walls of which were very thin, and exhibited within a rotation (cyclosis). [The universal appearance of these rotating streams in the root-hairs of Phanerogams I have already proved. — Mey.~\ M. Morren observed, that in some of these hairs the glo-bules collected together in masses and formed a kind of par-tition, by which the cyclosis was prevented ; indeed he be-* Translated and communicated by Henry Croft, Esq. f De la Structure ligneuse du Gui. Comptes Rendus 1839, p. 204. j Comptes Rendus, p. 215. § Notice sur une nouvelle espece de Malaxis, &c. Bull, de l'Acad. de Sci. de Bruxelles, torn. v. No. 8.
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