- past participle
- present participle
soft spongelike central cylinder of the stems of most flowering plants
kernel, substance, core, center, centre, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, pith, sum, nitty-gritty (verb)
the choicest or most essential or most vital part of some idea or experience
"the gist of the prosecutor's argument"; "the heart and soul of the Republican Party"; "the nub of the story"
remove the pith from (a plant)
The soft spongy substance in the center of the stems of many plants and trees.
The essential or vital part.
To extract the pith from (a plant stem or tree).
To kill (especially cattle or laboratory animals) by cutting or piercing the spinal cord.
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; outside followed by a ring of phloem. While new pith growth is usually white or pale in color, as the tissue ages it commonly darkens to a deeper brown color. In trees pith is generally present in young growth, but in the trunk and older branches the pith often gets replaced - in great part - by xylem. In some plants, the pith in the middle of the stem may dry out and disintegrate, resulting in a hollow stem. A few plants, such as walnuts, have distinctive chambered pith with numerous short cavities. The cells in the peripheral parts of the pith may, in some plants, develop to be different from cells in the rest of the pith. This layer of cells is then called the perimedullary region of the pithamus. An example of this can be observed in Hedera helix, a species of ivy. The term pith is also used to refer to the pale, spongy inner layer of the rind - more properly called mesocarp or albedo - of citrus fruits and other hesperidia. The word comes from the Old English word piþa, meaning substance, akin to Middle Dutch pitt, meaning the pit of a fruit.