THE SEEDLING AND YOUNG PLANT.
vertically above the bud—i.e., the sixth leaf up the stem. Knowing this, we of course know how the branch is joined to the stem. Several other small strands also are formed, as at z, to complete the filling up the gap, and these may be called completing bundles. These connecting and completing bundles enable the young shoot as it develops from the bud to inclose its own pith in a cylinder of vascular tissue continuous with that of the parent shoot.
We thus see that the vascular bundles form a connected system in the leaves, buds (i.e., young branches), and stem, and it only remains to add that they are joined below to those of the root-system, with which, in fact, they took origin in the very young embryo. Hence, if we were to remove the whole of the softer tissues of the oak-plant, we should have a model of it left in the form of a more or less open basket-work of vascular bundles. It is necessary to bear this in mind, as some important conclusions follow from it subsequently.