yerba buena, trailing evergreen perennial (Micromeria chamissonis) of the family Labiatae (mint family). It is native to W North America and especially common to woodland areas along the Pacific coast. Its aromatic leaves were gathered by the Native Americans of California for use in a medicinal tea. Yerba buena is classified in the division Magnoliophyta, class Magnoliopsida, order Lamiales, family Labiatae.