Folk-Tale Variations

I read the folklore "The Snake and the Princess," then I read the other variations of this text and found that while some are similar, others vary greatly.  One i found that was very different from the others was "The King Lindorm."  In this variation, a queen who wants children eats a rose petal to have a baby daughter but gets greedy and also eats the rose petal that would give her a baby boy.  When her child is born it is a lindorm.  The lindorm threatens to eat the kingdom if his father doesn't give him a bride and when the lindorm gets the bride, he eats her.  This happens two more times, except the third bride talked to a witch and the witch told her to beat the lindorm until he was submissive and then he would be nice and not eat her.  This worked and the lindorm and the bride had two children.  They sent a letter to the lindorm's father but they got mixed up and the father thought she had given birth to two dogs and he said they could stay until he got back but they got mixed up again and she thought he said she had to burn them so she sent them away to be safe and went off into the woods.  When the lindorm returned, he was dismayed his wife had gone and after fetching his children, he went off to get his wife and when he found her, he explained everything and they were happy again.  This was very different from the other texts, because in most of them, the mother promised her daughter to the snake to be married and the snake married the daughter and then he either turned into a handsome prince, or stayed a snake and the family lived happily.  Another common ending was the mother and her children turning into birds after a tragedy, usually involving the death of the snake.  While all the stories were different, they all had a snake marrying a human girl and then they had children and there was almost always magic involved.