. L'anatomie comparée des organes végétatifs des phanérogames marines et de fougères. L'anatomie des plantes phanérogames marines ; ; Fougères. Se termine ET LES CONNEXIONS DES FAISCEAUX. 381 à savoir s'allongent ; mais ils sont en moyenne plus courts et plus larges, et ont des surfaces de terminal, qui ne sont que peu obliques, et peut même être à l'horizontale. Comme la distance du bord intérieur augmente, leur longueur diminue rapidement, tandis que leur largeur augmente, de sorte que dans la partie extérieure de la frontière, ils ne sont pas plus longtemps, et sont souvent encore plus courtes qu'elles sont larges, étant semblable à la forme et à la taille de cellules parenchymateuses voisins. L

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. Comparative anatomy of the vegetative organs of the phanerogams and ferns. Plant anatomy; Phanerogams; Ferns. ENDS AND CONNECTIONS OF THE BUNDLES. 381 namely elongated; but they are on the average shorter and wider, and have terminal surfaces, which are but little oblique, and may even be horizontal. As their distance from the inner edge increases, their length rapidly diminishes, while their width increases, so that in the outer part of the border they are not longer, and are often even shorter than they are broad, being similar in form and size to the neighbouring parenchymatous cells. These conditions appear in a special form in Podocarpus IVIeyeriana, Thuja gigantea, and in the Pines and Abies excelsa. In the two first-named the border is very broad, it projects deeply into the middle of each half of the leaf in the form of a flat wing. Its tracheides, with the exception of the innermost, are, with reference to the diameter of the leaf, much broader than long, thus -having their greatest diameter directed towards the edge of the leaf; they form rows running towards the latter, . Fig. 184.—Juniperus communis (225). Median vascular bundle of the leaf, g- xylera; c isolated sclerenchymatous fibres at the outer border of the phloem; t border, consisting of tracheides with bordered pits and cross beams. The parenchymatous cells occurring near or between the latter are dotted in a granular manner. which are often interrupted, but are in contact with one another, and might be termed a narrow-meshed net of uniseriate vascular bundle terminations. In the connate sheathing-base of the flat pair of leaves of Thuja gigantea, the border of tracheides of each leaf is expanded into a low wing, which runs to meet that of the opposite leaf, and unites with it to form a transverse girdle. In the Abietineae last-mentioned the pair of vascular bundles lies in an approxi- mately cylindrical central portion of the leaf, which is free from chlorophyll, and is se- parated from the

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