Fig. 5.1-2. Transverse section of wood of Drimys (no common name). The large, more or less square cells with pink walls are sclerenchyma cells. The white space in the center of each fiber is the lumen where the protoplast had been located, but there is no sign of protoplasm now – this sample may have been collected from a dead piece of lumber or from the dead heartwood of a tree. The narrow white gaps in the walls are pits, (arrows) regions where the cells did not deposit any secondary wall interior to the primary wall.