This is from the Roman poet Ovid's story of Tiresias, in the Metamorphoses. The Metamorphoses, as its name implies, is the story of physical transformations.
In the Metamorphoses Ovid retells many of the Greek myths, especially those where, by the intervention of the gods, a mortal is turned into something less than human.
In connection with Tiresias' adventures in gender-shifting, Tiresias had recently been blinded by Juno (known as Hera in Greek mythology). Jupiter (known as Zeus in Greek mythology) then made him a prophet, in which capacity he quickly gained a reputation for being infallible in his answers to questions about the future. Sometimes, however, the answers of Tiresias were as opaque as those of any other fortune-teller.
Liriope, a naiad, became pregnant with the child of the river god Cephisus. When their child was born, Liriope named him Narcissus. When she asked the blind seer Tiresias if her son would live a long life. his answer was a qualified affirmative: Narcissus would live a long time if he never got to know himself.
Narcissus was so handsome everyone loved and desired him, but Narcissus was too proud to offer his love in return. His rejection of one would-be lover, Echo, turned her from an unhappy nymph into the barest wisp of what she had been. Echo shriveled up until all that was left of her was her voice, what we now call by her name.
Not all the would-be lovers of Narcissus were so passive. One of them took his complaint about rejection to the goddess of vengeance, Nemesis. The rejected suitor asked the goddess Nemesis to make Narcissus fall in love with himself, but simultaneously to be incapable of accepting his own love. Nemesis obliged....
On a hot day Narcissus bent down to drink from a clear, silvery pool. As he drank, he saw a beautiful image in the pool. He had never before caught a glimpse of himself. Narcissus fell in love with his own reflection. He tried to kiss and embrace it -- encouraged because he saw the other raising his lips to meet Narcissus' own -- but couldn't. Narcissus could do nothing except keep trying. In time he realized he was in love with his own reflection. Since he knew he could never hold himself, he despaired and realized he couldn't live any longer. He beat his breast and died. When his naiad sisters went out to bring him back for burial, the body was gone. In its place was a lovely yellow-centered white flower, the narcissus.