Over the weekend, my daughter Emma and I picked a posy of flowers for her mom. I was helping her tie a ribbon around the bunch when Emma stopped to pulled one green stalk out from the tiny bunch. She eyed the base of the stem curiously.

“This one’s square,” she told me, looking puzzled.

I took the greenery from her hands to confirm. She was right – though my expectation was for the stem to be round, this one was very clearly square. It had simple leaves that were opposite each other and smelled divine. We went straight to a plant book for some answers. In it, we learned quickly that if you pick a plant with a distinctly square stalk, then it is very likely a member of the mint family.