Sclerenchyma cells form sclerenchyma tissue. These cells have thick, tough secondary walls that are embedded with lignin. At maturity, most sclerenchyma cells are dead and function in structure and support. Sclerenchyma cells can occur in two forms:
- Sclereids are sclerenchyma cells that are randomly distributed throughout other tissues. Sometimes they are grouped within other tissues in specific zones or regions. They are generally as long as they are wide. An example would be the gritty texture in some types of pears. The grittiness is due to groups of sclereid cells. Sclereids are sometimes called stone cells.
- Fibers are sometimes found in association with a wide variety of tissues in roots, stems, leaves, and fruits. Usually, fiber cells are much longer than they are wide and have a very tiny cavity in the center of the cell. Currently, fibers from over 40 different plant families are used in the manufacture of textiles, ropes, string and canvas goods to name a few.