Note 7 — Chapter V · PATH OF MOVEMENT OF WATER IN PLANTS.

This ring and the bundles separate the stem into two regions, an outer one composed of large cells with thin walls, known as the cortical cells, or collectively the cortex. The inner portion, corresponding to what is called the pith, is made up of the same kind of cells and is called the medulla, or pith. When the cells of the cortex, as well as of the pith, remain thin walled the tissue is called parenchyma. Parenchyma belongs to the group of tissues called fundamental.