Pith

A person is called pithy when they are concise and forcefully expressive. Did you know that many plants can also by pithy?

Elder shoot cut to show white pith in the center, surrounded by yellow wood (MPF)

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Pith, also known as medulla, is a type of plant tissue that stores and transports nutrients. Typically, it is very soft and spongy.


Stem pith

In the very center of many stems, you can see a spongy area. This is particularly noticeable inside sunflower stems and their central cores, or steles. This is pith. Xylem surrounds the pith, and phloem are outside of the xylem. When pith first develops, it is white. As it ages, it can darken. In some plants, the pith may disintegrate completely, while, in others, the pith may have a chambered structure.

Chambered pith of walnut stem (MPF)

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Tree pith

If you were to take a cross-section of a tree trunk, from the outside in, you would see bark, medullary rays, cambium, sapwood, heartwood, and a dark, spongy center used to carry essential nutrients. This dark area is the tree’s pith.

Dark center spot in yew is pith (MPF)

Fruit pith

While the bitter white tissue found on the inside of a citrus rind is often called pith, that tissue is actually mesocarp, or albedo. The white membranes found inside pepper plants, however, really are pith.


If you happen to have a sago palm, the pith is highly toxic to animals when raw, but it is commonly used as a starchy food source in Micronesia. The toxins are removed and the starch is used much like tapioca.