- pennyroyal, American pennyroyal, Hedeoma pulegioides - erect hairy branching American herb having purple-blue flowers; yields an essential oil used as an insect repellent and sometimes in folk medicine
--1 is a kind of herb, herbaceous plant
--1 is a member of Hedeoma, genus Hedeoma
--1 has substances: pennyroyal oil, hedeoma oil