Sclerenchyma is a type of plant tissue characterized by its thick, lignified cell walls, which provide structural support and strength to the plant. It consists primarily of two types of cells: fibers, which are long and slender, and sclereids, which are shorter and irregularly shaped. Sclerenchyma is often found in areas of the plant that have stopped growing, such as in stems and seed coats. Its rigidity helps protect the plant and maintain its shape.