330 Meyen's Report for 1839 on Physiological Botany. 



XXXVIL— Report of the Results of Researches in Physiolo- 

 gical Botany made in the year 1839. By F. J. Me yen, 

 M.D., Professor of Botany in the University of Berlin*. 



[Continued from p. 275.] 



M. MiRBELf has given us some very interesting researches 

 on the "Generative sap" of the roots of the Date-palm (Phoenix 

 dactylifera) ; this sap he calls " Cambium." The cambium 

 deposits itself in layers in the stems and boughs of the mono- 

 and di-cotyledons, partly in the large interstices which remain 

 between the utriculi or cells (schlauche), and partly in the cavi- 

 ties of the cells and tubes. From it proceeds the organization ; 

 and the principal object of this treatise is to follow, by a series of 

 observations, the transition of the cambium from an amorphous 

 state into that of continuous cellular tissue and of independent 

 utriculi. The aim of the observations is no less than the pro- 

 foundest study of the formation of all the tissues of which the 

 different vegetative organs are composed. On examination of 

 the roots of the date-tree, there are seen in transverse sections 

 masses of cambium with a granular surface, at least it appears 

 so, and this is seen with all possible distinctness. It is certain 

 the appearance of the granulations (mamelons) precedes that 

 of the cells ; often in sections from a root of determinate age 

 (viz. very young) in the centre of each granulation a dark spot 

 is visible, and this is an unequivocal sign of the formation of 

 the cavity of a cell ; a larger spot shows the increase of the cell. 

 In this latter case there was nothing granular to be seen, and 

 the undivided partitions which bounded the neighbouring 

 cells were thinner, in proportion as the cavities of the cells 

 had increased in size. Frequent comparisons showed that 

 this metamorphosis takes place without increase of substance. 

 The cells do not remain long in this state ; their sides extend, 

 and become covered with minute papillae, which are arranged 

 like the squares of a chess-board, and which, although of 

 firmer consistence than at first, still contain much moisture. 

 Shortly afterwards these cells, which until then had had 

 no determinate form, assume the shape of more or less re- 

 gular hexagons (on transverse sections), their sides ex- 

 tend, become thin, dry, and stronger; the papillae vanish, 

 and there appear in their place horizontal, parallel, fine 



* Translated from the German, under the direction of the Author, and 

 communicated by Henry Croft, Esq. 



f Nouvelles notes sur le Cambium, extraites d'un travail sur la Racine 

 du Dattier.— Compt. Rend. 29 Avril, 1839. Ann. des Sci. Nat., Part. Rot. 

 1839, I. 321. PL 11—15. With larger plates in the Archive du Museum 

 d'Hist. Nat. I. p. 305. 



