The green ground tissue in leaves is called mesophyll tissue. There are two types of mesophyll tissue.
1. Palisade parenchyma: Palisade parenchyma cells are long, densely packed, non-vesicular and vertically arranged.
2. Spongy parenchyma: Spongy parenchyma cells are round, thin, fibrous and loosely arranged.
Function: Mesophyll tissue produces food through the process of photosynthesis.5. Water sac: Water accumulates in the skin cells of ice plants and takes the form of a sac. In winter this water turns into ice. For example, Mesembrayanthemum crystallinum.