Pith, or
medulla, is a
tissue in the
stems of
vascular plants. Pith is composed of soft, spongy
parenchyma cells, which store and transport nutrients throughout the plant. In
eudicots, pith is located in the center of the stem. In
monocots, it extends also into flowering stems and roots. The pith is encircled by a ring of
xylem; the xylem, in turn, is encircled by a ring of
phloem.