Very young ovules have a single thick integument consisting of densely packed thin-walled parenchyma cells that are uniform in shape and size (Fig. 1d). After anthesis, the nucellus degenerates completely and the inner layers of the integument enlarge and divide periclinally (Fig. 1d). The outer epidermal cells are more or less isodiametric (Fig. 1d). As periclinal divisions continue along the inner layers of the integument the outer layers are crushed and eventually degenerate (Fig. 1e). The outer layers degenerate according to a specific pattern to establish the corrugated appearance of the mature seed coat in surface view (Fig. 1f). The epidermal cells divide anticlinally and further contribute towards the irregular surface pattern ofmature seeds (Fig. 1f).