Meristems are found in both roots and shoots. Primary meristems make the shoot or root grow longer. This kind of growth is called primary growth. A shoot apical meristem is found within each bud. A root apical meristem is found at the tip of each root, and is protected by the root cap.
Secondary meristems make the stem or root grow larger in diameter.
This kind of growth is called secondary growth. Not all kinds of plants are capable of secondary growth. Secondary growth gives rise to wood, and plants that are not capable of secondary growth do not develop wood. Because plant growth is indeterminate, each meristem can potentially develop into a complete plant. This means that it is very easy to clone plants, and many plants can grow from cuttings or broken plant parts.