Mentha pulgeium- Pennyroyal Tincture – The Herb Shoppe
Pennyroyal – Eagleridge Seeds
Todsen's False Pennyroyal / Center For Plant Conservation
Pennyroyal Seeds (Mentha pulegium)
A manual of weeds : with descriptions of all the most pernicious and troublesome plants in the United States and Canada, their habits of growth and distribution, with methods of control .