- pennyroyal, Mentha pulegium - Eurasian perennial mint have small lilac-blue flowers and ovate leaves; yields an aromatic oil
--1 is a kind of mint
--1 has substances: pennyroyal oil - 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
--2 is a kind of herb, herbaceous plant
--2 is a member of Hedeoma, genus Hedeoma
--2 has substances: pennyroyal oil, hedeoma oil