Sclereids are the modification of

Sclereids are special sclerenchymatous cells found in the cortex, pith, phloem, hard seeds, nuts and stony fruit. Sclerenchymatous cells are long, narrow, thick and lignified, usually pointed at both ends. The cell wall is evenly thickened with lignin and sometimes is so thick, that the cell cavity or lumen is absent. Nucleus is absent, and hence the tissue is made up of dead cells.