Definition - What does Pith mean?
Pith is the tissue that is located in a plant’s stem and roots. It is soft and spongy. New pith growth appears white but as it matures it usually turns brown.
The pith functions by transporting nutrients throughout the plant and storing nutrients within its cells. It is made up of distinctive parenchyma cells. The cells are large but have thin walls. The cells of the pith readily fill up with nutrients and water and swell.
MaximumYield explains Pith
Pith is often called medulla. Tree’s have a pith when young but as the tree matures its pith transforms into the xylem. The pith in the middle of some plants often dries completely out so that the stem of the plant becomes hollow.
Vascular plants use the pith to successfully flow water up and down the stem and into the roots and leaves. Non-vascular plants such as mosses and algae have no pith.
The pith is very visible in citrus fruits where it appears as white spongy material.
In walnuts, the pith is the hardened chambers inside the shell that divides the nuts.