Parenchyma

Parenchyma, cellular tissue in plants in which the individual cells are not elongated to more than four times their breadth. It may be loose or spongy, with spherical cells and large intercellular spaces, as in the mesophyll of many leaves; compact and dodecahedral, as in some pith; nmriform, or brick-shaped, as in periderm; or stellate, as in the "pith" (mesophyll) of the rush.