Peppermint flowers (Mentha x piperita). This is a hybrid mint that is a cross between watermint (Mentha aquatica) and spearmint (Mentha spicata). It is used in herbal medicine to treat flatulence and to aid digestion. It can be applied to the skin to soothe and relax aching muscles. It is also used as an ingredient in cooking and is a good source of manganese, vitamin C and vitamin A.