that there are 18 or 19 true mints. There are more combinations or hybrids. I'm not sure of the number exactly. There are three mints that should never be used as food, Corsican mint (Mentha requienii), Japanese mint (Mentha arvensis var. piperascens) and the pennyroyals (Mentha cervina, Mentha pulegium) all of these contain a toxic oil that can cause convulsions and coma. The mint family, the family Lamiaceae or Labiatae is a combination of herbs and ornamentals that includes Mentha. The mint family includes among other herbs, basil, rosemary, thyme, marjoram, oregano, lemon balm, catnip, lavender, hyssop, horehound, patchouli and sage. I think you have heard of at least some of these if not all of these herbs. The other link that they have is that their stems have four sides. The ornamentals include Bee Balm (Monarda), obedience plant (Physostegia virginiana) and Russian sage (Perovskia atriplicifolia).
There is a wonderful herb farm in Ohio and I have written about them several times in my blog called Mulberry Creek Herb Farm. While they no longer ship plants, their on-line catalog will give you a lot of information about mints. Papa Geno's also has a lot of information. The photo above is silver mint. Most of my other mints, peppermint in the backyard, spearmint (yes, it is a mint) in the front yard, orange mint, basil mint and pineapple mint are all in the ground. They are easily pulled out when out of bounds. I would love to have them all in containers, but we don't have room to take them in in the winter. One problem I do have with the peppermint especially that when it flowers, it does spread seeds. So I am pulling plants out across the garden to make sure that it does grow in too many places. I hope I have helped be less herbal challenged, Lifeshighway. I will take a photo of each of mine and will post them in the coming days. If you have more questions, please let me know! Hope you have all had a great day! Talk to you later.