button snakeroot n coarse prickly perennial eryngo of United States thought to cure rattlesnake bite n coarse prickly perennial eryngo with aromatic roots; southeastern United States; often confused with rattlesnake master n any of various North American plants of the genus Liatris having racemes or panicles of small discoid flower heads Synonym(s) rattlesnake master rattlesnake's master Eryngium yuccifolium Eryngium aquaticum blazing star gayfeather gay-feather snakeroot