stomata may be found only on the upper epidermis and submerged leaves may lack stomata entirely. Most tree species have stomata...The epidermis is thin and does not contain chloroplasts. The mesophyll is disintegrated into many lacunae; the cells are large and have large vacuoles. Chloroplasts are of the granal type with plastoglobuli and starch granules. The leaf has three vascular bundles, one large bundle and two smaller ones located in the upper mesophyll tissues, forming a kind of triangle with the central bundle. The xylem is well developed and shows spiral tracheids. As a consequence of greater lacunar space, the diameter of the submerged leaf is about two or three times larger, as compared with the aeriel leaf. The submerged leaf seems to be distended. The epidermis of the submerged leaves, the central vascular bundle is in direct contact stomata of theHelleborustype. In submerged leaves, the central vascular bundle is in direct contact with the surrounding water. The same observation was made in aerial leaves after submersion, whereas in normal aerial leaves the central bundle is closed.