Vervain
.Called “holy herb,” from its use in ancient sacred rites. Also called “pigeonsʹ grass,” “Juno’s tears,” and “simpler’s joy.” Supposed to cure scrofula, the bite of rabid animals, to arrest the diffusion of poison, to avert antipathies, to conciliate friendships, and to be a pledge of mutual good faith; hence it was anciently worn by heralds and ambassadors. (See Roodselken.)
Verbena is the botanical name.