How does Odysseus prove his identity to his father

From the text:

"If you really are my son Ulysses," replied Laertes, "and have come back again, you must give me such manifest proof of your identity as shall convince me."

"First observe this scar," answered Ulysses, "which I got from a boar's tusk when I was hunting on Mount Parnassus. You and my mother had sent me to Autolycus, my mother's father, to receive the presents which when he was over here he had promised to give me. Furthermore I will point out to you the trees in the vineyard which you gave me, and I asked you all about them as I followed you round the garden. We went over them all, and you told me their names and what they all were. You gave me thirteen pear trees, ten apple trees, and forty fig trees; you also said you would give me fifty rows of vines; there was corn planted between each row, and they yield grapes of every kind when the heat of heaven has been laid heavy upon them."