A meristem is a type of plant tissue that consists of undifferentiated cells capable of continuous division and growth. These cells are responsible for the formation of new tissues and organs in plants. Meristems are primarily found in areas of active growth, such as the tips of roots and shoots, where they contribute to the plant's length and overall development. There are two main types of meristems: apical meristems and lateral meristems. Apical meristems are located at the tips of roots and shoots, promoting vertical growth, while lateral meristems, such as the cambium, contribute to the thickness of stems and roots. Together, these meristems play a crucial role in the growth and regeneration of plants.