The anatomy of the bark of Robinia pseud-acacia, Linné (False acacia or common locust) / by Pierre Élie Félix Perrédès.

  • Perrédès, Pierre Élie Félix.
Date:
[1901]
Catalogue details

Licence: In copyright

Credit: The anatomy of the bark of Robinia pseud-acacia, Linné (False acacia or common locust) / by Pierre Élie Félix Perrédès. Source: Wellcome Collection.

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    tubes are shortly segmented, the segments being but three or four times as long as the cells of the bast parenchyma (Fig. 11). In the vicinity of the cambial region the sieve-tube walls are less thickened, although they still retain their jelly-like ap¬ pearance (see Fig. 9). 4.—The Medullary Bays.—The cells of the medullary rays are thin-walled, tabular, and elongated in a radial direction, being radially extended when seen in transverse and in radial longitudinal sections [m.r., Figs. 9 and 11), and approximately isodiametric in tangential longitudinal section (m.r., Fig. 13). The medullary rays themselves are usually from three to four cells wide, as has already been stated, and about twenty cells deep, on the average, although they may be as little as two or as much as over fifty deep. Cell-Contents. The contents of the elements of the outer bark consist mostly of brown colouring matter blackened on treatment with ferric chloride. The fibres of the inner bark have few contents, if any, and those of the sieve-tubes are slight.* The cells of the medullary rays and those of the bast paren¬ chyma are, on the other hand, filled with proteid material giving the usual colour reactions with iodine and with Millon’s reagent, that with the latter reagent being particularly striking ; details are shown in Figs. 16-18. In Fig. 16 the action of alcohol is represented. The section from which Figs. 17a and 17b were sketched, had been treated with Schulze’s solution ; here the contents, although somewhat shrunken, have a fairly plump and well-fed appearance, the lighter areas (hyd.) are vacuoles (these, with their bounding membranes, constitute the Hydroleucites of Van Tieghem). Figs. 18a and 18b show the effects of Millon's reagent ; the contents in this case are shrivelled up into a shapeless mass. Starch is entirely absent, with the doubtful exception of the more darkly staining and ill-defined patches in the gelatinous * An investigation of the sieve-tube contents has not been attempted in dry material such as that at present under examination; nor is this necessary, as the subject has been fully worked out by Strasburger in « Ueber den Bau und die Verrichtungen der Leitungsbahnen in den PHanzen,’ Jena, 1831, p. 166-200, and also by Baccarini in Malpighia, Vol. VI.,1892, Pp. 55-57 and Plate IV. (‘Intorn® ad una particolaritA dei vasi cribrosi nelle Papilionacoe ’).