there is a wild variety of pennyroyal and it usually has larger leaves than the kind you would buy from a nursery. Normally there are many cultivars (short for cultivated variety), of any plants that are domesticated. there are different wild mints but then you can buy 100's of cultivars like chocolate mint, grapefruit mint, 10 kinds of spearmint, etc. Pennyroyal is a mint too. good for repelling fleas on cats & dogs, but cats & dogs hate the smell of most mints. Ever noticed the breath.marvella said:in the smokies, it is not at all uncommon to find several varieties of the same kind of plant. amazing biodiversity!!!!