Mentha pulegium, commonly pennyroyal, also called squaw mint, mosquito plant and pudding grass
Crushed pennyroyal leaves exhibit a very strong fragrance similar to spearmint.
Pennyroyal is a traditional culinary herb, folk remedy, and abortifacient.
The essential oil of pennyroyal is used in aromatherapy.
These will come in a 9cm plant pot and will need replanting.