Leaf scars on a stem of Fatsia japonica. The picture shows cut lengths of a stem of F. japonica that has shed its leaves. The horseshoe shaped area on each stem is a leaf scar. The "nails" of the horseshoe are bundle scars, showing the sites of vascular bundles within the leaf stalk. The small brown surface protuberance just above the scar is a dormant bud. Deciduous woody plants shed leaves actively by the process of abscission. At the base of the leaf stalk a zone of specialised cells develops. On the leaf side, an abscission layer of small cells with weak walls is formed. On the stem side, cells become thickened with a cork-like substance, suberin - this is the protective layer, which is visible in the picture. After leaf fall, the interior of the stem is thereby insulated from the effects of winter weather. The bud may, but not always, subsequently develop into a new side shoot.