Phyllis was the daughter of Sithon or of Lycurgus, king of Thrace. According to whichever story one reads, she married either Acamas or Demophon. Whoever it was, when her husband sailed away and did not return to her by the time he had promised, she hanged herself in despair and was changed into an almond tree.

This tree, says the Demophon version (as told by Apollodorus), had no leaves. When Phyllis had changed into the tree, Demophon returned to Thrace and hugged it, whereupon it sprouted leaves.

From this incident, we are told, the Greek word for 'leaves', formerly petala (the plural of petalon, which is probably related to 'petal'), became phyllas. Hence her name. It was this Phyllis, via English Renaissance and later poets, that gave her name to modern Phyllises (who are less common now than they were fifty years ago).