<P> Sclereids are a reduced form of sclerenchyma cells with highly thickened, lignified cellular walls that form small bundles of durable layers of tissue in most plants . The presence of numerous sclereids form the cores of apples and produce the gritty texture of guavas . </P> <P> Although sclereids are variable in shape, the cells are generally isodiametric, prosenchymatic, forked, or elaborately branched . They can be grouped into bundles, can form complete tubes located at the periphery, or can occur as single cells or small groups of cells within parenchyma tissues . An isolated sclereid cell is known as an idioblast . Sclereids are typically found in the epidermis, ground tissue, and vascular tissue . </P>

Plant fibers embedded in the fruit ground tissue of the pear are called schlerids