Meristematic tissue refers to a group of specialized regions in plants where cells continuously divide, enabling growth and development. There are three types of meristematic tissues based on where they are located in the plant. 

1. Apical meristemsare found at the tips of stems and roots, assisting the plant in growing longer.
2. Intercalary meristemsare at the bases of leaf blades and nodes. They permit monocot leaves (e.g. grass blades) to grow longer even after being cut repeatedly. 
3. Lateral meristemshelp the plant grow thicker or wider as it matures.