Thanks so much…Finn will be so happy with these findings! I, too, had no idea so many special mint varieties existed…pineapple? Wow…I’ll have to think about that!
Believe it or not, I just got many lovely herbs and plants in the mail today from a wonderfully kind friend…including both chocolate mint and pennyroyal!
Indeed, pennyroyal is quite poisonous when ingested by any living being (us humans, too)! Agreed: the look of it wouldn’t really be putting you at risk for mistaking it as an edible variety. It’s very pretty, but to my eye, doesn’t look like the mints we consume.
Interesting side note for anyone who wants to know more as Halloween approaches:
Pennyroyal was one of the key ingredients in "flying balms" used by witches many years ago to induce altered states. They applied it, combined with other herbs, topically to sensitive areas of the skin, then lay on the floor and waited for the "fun" to begin. It is this altered state, some call it the astral realm, where the slightly misconstrued idea of witches "flying" on brooms came from. In reality, they would use their besoms as spiritual tools, symbolically sweeping away negative energy and unkind people. 
We hung some Halloween decorations today. I’m all in the mood for it already!