ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 775 



Network of Cells surrounding the Endoderm in the Roots of Cruci- 

 ferae. * — M. P. van Tiegbem states that he has already shown that a great 

 number of the Couiferse, more particularly Cupressine^ and Taxineaj, have 

 the cells of the cortical portion of the young root in contact with the 

 endoderm strengthened by ligneous thickenings. An anatomical and 

 physiological arrangement similar to this has been described by Woronin 

 as occurring in the cabbage, and the author has recently studied a number 

 of Cruciferse ; the results of his investigations are detailed. 



A series of transverse and longitudinal sections were made of the root 

 of Sinapis alba, before the formation of secondary tissue ; these were stained 

 with fuchsin. All the cells of the last cortical layer but one were exactly 

 superposed to those of the endoderm, and the cells of the ante-penultimate 

 layer were provided towards the middle of their radial and transverse faces 

 with a strong thickening band, which was stained red by the reagent. 

 From each band a series of lesser bands spread towards the interior. The 

 author states that a network of cells surrounding the endoderm occurs 

 in Cheiranthus, Alyssum, Koniga, Farsetia, Berteroa, Vesicaria, Cochlearia, 

 Malcolmia, Sisijmbrmm, Brassica, &c, ; while in Matthiola, Nasturtium, 

 Barbarea, Arabis, Turritis, Hesperis, Erysimum, Camelina, Diplotaxis, 

 Iberis, &c., this arrangement has not been found to occur. 



Cortical Fibrovascular Bundles in Lecythidese and Barringtoniese.j — 

 In some genera belonging to these orders Prof. M. M. Hartog finds a 

 complete system of cortical bundles external to the pericycle, anastomosing 

 with the leaf-traces at the nodes. They have often a complete circle of 

 exogenous wood without pith, and a crescent of phloem on the outer side ; 

 they are all but concentric. 



Passage of Fibrovascular Bundles from the Branch to the Leaf.| — 

 Dr. C. Acqua, agreeing generally with the observations of Petit, § dis- 

 tinguishes 13 types of arrangement and distribution in the passage of the 

 fibrovascular bundles from the branch to the leaf, dependent on the number 

 of distinct cords of bundles which enter the leaf, the degree to which these 

 cords unite or anastomose, and other points. Without attaching too much 

 importance to the structure of the leaf-stalk, this may yet, in many cases, 

 be usefully observed for systematic purposes. In all cases observed, where 

 the bundles enter the leaf in a single cord or arc, the leaf itself was 

 simple. 



Second Primary Wood of the Root-lj— M. P. van Tieghem states that 

 it is well known that the primary wood of the root consists of a certain 

 number of radiating woody bundles developed centripetally, alternating 

 with a like number of liber-bundles, so that secondary wood, when it is 

 produced, consists of vascular tangential bundles developed centrifugally, 

 superposed internally to the liber-bundles. It is admitted that all the 

 primary wood of the root is contained in the centripetally developed 

 bundles, but it does not follow, as is usually supposed, that all the 

 secondary wood is contained in the centrifugally developed bundles. It 

 certainly is so in a great number of plants ; but in many others the arrange- 

 ment is different. The object of this paper is to explain the structure of 

 the latter. 



The author designates the centripetally formed vascular bundles alter- 

 nating with the liber-bundles, as protoxylem, and the centrifugally formed 



* Bull. See. Bot. France, xxxiv. (1887) pp. 125-30. 



t Rep. Brit. Assoc. Birmingham Meeting, 1886, p. 706. 



t Malpighia, i. (1887) pp. 277-82. § See this Journal, ante, p. 261. 



II Bull. Sec. Bot. France, xxxiv. (1887) pp. 101-5. 



