Hedeoma pulegioides (American pennyroyal, or American false pennyroyal) is a species of Hedeoma native to eastern North America, from Nova Scotia and southern Ontario west to Minnesota and South Dakota, and south to northern Georgia and Arkansas.
It is a low-growing, strongly aromatic herbaceous annual plant from 15–30 cm tall, with a slender erect much-branched, somewhat hairy and square stem. The leaves are small, thin, and rather narrow, with a strong mintlike odor and pungent taste. The flowers are pale blue, monoecious, produced in small clusters; it flowers from mid to late summer.
The name pulegioides is derived from the Latin pulegium and oides, and means "like pennyroyal". Hedeoma pulegiodes is also known by the synonyms Melissa pulegioides L. (basionym), Cunila pulegioides (L.) L., and Ziziphora pulegioides (L.) Desf.
The term "Pennyroyal" (or Pennyrile, from a dialectal pronunciation) is also used to describe a geographic province of western Kentucky, the Pennyroyal Plateau, where H. pulegioides grew in profusion sufficient to lend its name to the whole area.
- USDA Plants Profile: Hedeoma pulegioides. Accessed June 19, 2007.
- Germplasm Resources Information Network: Hedeoma pulegioides
- Plants for a Future: Hedeoma pulegioides. Accessed June 19, 2007.
- NEWCrop USDA Miscellaneous Publication No. 77: The Herb Hunters Guide: American Medicinal Plants of Commercial Importance. NEWCrop's online transcription of the 1930 USDA publication March 11, 1998. Accessed June 19, 2007.
- Griffith, Chuck. Dictionary of Botanical Epithets. Accessed June 19, 2007.
- BONAP (Biota of North America Program). Synonymized Checklist of the Vascular Flora of the United States, Puerto Rico, and the Virgin Islands. Accessed June 19, 2007.