The pith is a part of the Ground tissue together with the cortex. The cortex is located to the outside and/or around the vascular bundles, while the pith is locate in the center of the stem.
Both the cortex and pith are composed mainly of parenchyma cells. On the other hand collenchyma cells give support to the stem and may occur under the epidermis in the cortex.
Pith is composed of soft, spongy parenchyma cells, which store and transport nutrients throughout the plant.
