. Studies in fossil botany . Paleobotany. LYGINODENDRON 367 passes out, a gap, filled by parenchyma, is left in the wood, which only closes up behind the bundle at a higher level (Fig. 129). When the leaf-trace leaves the wood of the stele, it is at first accompanied by its own secondary tissues, which, as seen in transverse section, form a fan-shaped mass on the outer side of the primary wood (see Fig. 129, ). As the strand. Fig. i-$\.—Lyginodendron oldhamium. Part of transverse section, from outer part of stele. jt2, secondary wood ; r, medullary rays ; ci, cambium ; />/j2, secondary
. Studies in fossil botany . Paleobotany. LYGINODENDRON 367 passes out, a gap, filled by parenchyma, is left in the wood, which only closes up behind the bundle at a higher level (Fig. 129). When the leaf-trace leaves the wood of the stele, it is at first accompanied by its own secondary tissues, which, as seen in transverse section, form a fan-shaped mass on the outer side of the primary wood (see Fig. 129, ). As the strand. Fig. i-$\.—Lyginodendron oldhamium. Part of transverse section, from outer part of stele. jt2, secondary wood ; r, medullary rays ; ci, cambium ; />/j2, secondary, >/z, primary, phloem ; , secretory sac ; pd, periderm. X 52. Phil. Trans., W. and S. Will. Coll. 1640. passes up through the pericycle, this secondary portion is gradually lost, and has usually disappeared at the level where the bundle divides into two (see Figs. 129 and 132). The collateral structure, however, is still maintained. It is only where the leaf-trace finally bends out, to enter the petiole, that this structure changes. Here the phloem begins to encroach on the inner side of the xylem, until, in the leaf-stalk itself, the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Scott, Dukinfield Henry, 1854-1934. London, A. and C. Black
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