Bulliform cells are the cell that is spread among the leaf's epidermal cells.They are essential for water storage. During stress circumstances, bulliform cells assist to roll leaves to avoid water loss through transpiration. Therefore, they control the process of transpiration. They unroll the leaves under favorable circumstances as well. Bulliform cells are discovered primarily in grasses.They are large, bubble-shaped epidermal cells occurring in groups of many monocots on the upper surface of the leaves. These cells are found on the leaf's adaxial or upper surface. They're usually around the middle vein. These cells are large, colorless and vacuum. When water is abundant, they absorb water and bulge and shrink when there is less water, curling the leaf, which helps to decrease water loss owing to evaporation.