Figure 6. SEM micrographs of the outer- and innermost layers of the Macadamia integrifolia seed coat: a) & b): epidermis, c) & d) inner testa layer.

The one cell-layer thick epidermis is composed of pancake-like cells, which form a smooth surface with many pores on the outside. The inner contour of the epidermis cells follows the shape of the sclereid cells. The inner testa layer is a thin homogeneous layer, which is connected to the cream-coloured or dark brown inner layers. The surface of the inner testa layer shows no pores (d).