Fig. 5.3-6. Transverse section through leaf of sweet olive (Osmanthus). The macrosclereids (red) in this leaf occur as idioblasts, that is, each is surrounded by cells that are not like itself. Consequently, their shape is easily visible. The small brown streaks and splotches in these are the remnants of the lumen, all the rest of the macrosclereid is secondary wall (each has a primary wall too thin to be seen here). These macrosclereids are so large, and are lying in varied directions, so as the microtome knife cut through the leaf, it often cut off one or both ends of each sclereid.