It is found in two separate areas. Cambium in buds produces tissue that increases the length of the stem. The cambium encircling the stem produces increased diameter or girth. Injury to the cambium layer in certain plants can kill the entire plant. There are many stem variations in plants.
Some variations are forms of food, such as potatoes and asparagus.
Others are forms sold in dormant condition for introduction into the landscape as new plants, such as dahlia tubers and tulip bulbs. The main function of leaves is food production for the plant. Leaves have evolved into many shapes and sizes, reflecting adaptations to the environment. Leaves are most commonly flat, broad and green. This maximizes their function of absorbing sunlight and transforming it into food.