Spearmint, mentha spicata
The flavor of spearmint in particular comes from a chemical called R-carvone, which gives the leaves their strong aroma and flavor. Mints are a part of the lamiaceae family which contains 236 genera and over 6,900 different species. Because of the nature of specie classification, the number of species and generas in any particular family, including lamiaceae, tends to change over time as species are reclassified and new plants are discovered, so these numbers are likely to change. The lamiaceae family contains, along with mint, common plants such as rosemary, thyme and sage, just to name a few.
leucas aspera, family lamiaceae
Mint specifically is under the genus mentha. This may sound familiar because of mint's essential oil, menthol. Plants under mentha are flowering and aromatic, and almost always perennial (they live for two years). Mint leaves are arranged in opposite pairs, and are usually downy with serrated edges. The leaves can come in a variety of different colors from all shades of green to blue or yellow. Mints do produce fruit, but these are generally just small, dry capsules containing one to four seeds. The flowers of these plants are arranged in a false whorl pattern called a verticillaster.
Verticillaster on a hedge nettle
Mints are considered to be invasive plants. They only grow to be about 10 to 120 cm tall, but they grow sideways very rapidly. They send out stems and roots around them to extend their reach, thus crowding out other plants near them. Some mint varieties are even sterile, meaning that this sideways expansion is the only way that they can reproduce. Mint plants prefer cool temperatures with moist soil and partial shade, but they are capable of growing in most environments.
Mint plants will grow almost anywhere.
The invasive quality of these plants makes them very easy to cultivate using stem cuttings, but they can pose a hazard to a garden if not properly contained. Mint oils are used in cosmetics and soaps as well as gum and toothpaste. There are many shampoos infused with mint, and perfumes that use these essential oils. Mint tea is also very popular and happens to be a very powerful diuretic (meaning that it makes you urinate).
One of Suave's mint shampoos.
Mint plants are good companion plants because they tend to ward off insects with their powerful odor. They cannot, however, protect against aphids or white flies. Because of this, campers will sometimes use mint leaves as insect repellents, but I wasn't able to find out if that actually works or not, so I'm skeptical. Mint oils also work as antipruritics, anti-irritants. That basically means that mint oils can sooth itching from rashes or bug bites. Mint's uses are all over the place, from medicine to food, and it is deeply ingrained in many cultures, not just American culture. I personally like spearmint gum, it tastes good and makes your breath smell fresh.