White mulberry (Morus alba) differs from Common or Black Mulberry by having longer-stalked berries and leaves which are hairless (rather than slightly hairy) on the underside. It is a native of China but has become naturalised in the Mediterranean. Its berries taste sweet well before they are ripe. Its leaves feed silkworms.
Trees and shrubs of the Mediterranean by Helge Vedel, translated from the Danish by Aubrey Rush (Penguin Guides, 1978), p.30.