"Clytie was a water-nymph and in love with Apollo, who made her no return. So she pined away, sitting all day long upon the cold ground, with her unbound tresses streaming over her shoulders. Nine days she sat and tasted neither food nor drink, her own tears and the chilly dew her only food. She gazed on the sun while he rose, and as he passed through his daily course to his setting; she saw no other object, her face turned constantly on him. At last, they say, her limbs rooted in the ground, her face became a flower, which turns on its stem so as always to face the sun throughout its daily course; for it retains to that extent the feeling of the nymph from whom it sprang."
-From The Illustrated Bullfinch's Mythology, text by Thomas Bullfinch.
As a child, I loved this story to pieces. Years later, after becoming obsessed with a Hans Christian Andersen version of The Little Mermaid story, and even later watching Disney's The Little Mermaid, I began to wonder if it wasn't the same story as Clytie. Perhaps the folktale evolved from the Greek myth.
In each story we have a mermaid falling in love with someone from the surface, despite the two worlds being unable to meet; the hapless mermaid pays a price. These stories each involve the change of the little mermaid into a different kind of creature-- a sunflower, a human, or a human soul in heaven. In each story, the little mermaid gives up her identity and her home to move to another realm as another kind of being.
Disney's story let the mermaid off easy. She turned into a human, got to marry her prince and have a Happy True-Love Ending, and the only real sorrow is her separation from her family. Andersen's folktale is both kind and cruel: although the mermaid achieves Christian redemption, she dies, and never in life gets to be with her true love. Bullfinch's myth falls somewhere in between. It is strange. The little mermaid is not separated from her love, precisely; nor must she pay with her life. Instead, she transforms into something completely different.
The moral of the story is not (as with Disney's) that true love conquers obstacles, nor is it (as with Andersen's) that love is an unselfish thing greater than death. The moral of the Greek tale is that love changes you into something different from what you were before.