What is meant by "the beautiful woman from a bad root," which was mentioned in a ḥadīth of the Messenger, may Allah's peace and blessings be upon him?

The Hadith, "Beware of the green things of dung," is very weak, and its meaning is a warning against a beautiful woman from a bad family, meaning she is beautiful but from a bad origin. She is likened to beautiful plants that grow on garbage dumps.