Mint, botanically Mentha, a genus of labiate plants, comprising about twenty species of perennial herbs, widely distributed throughout the temperate and sub-tropical portions of the globe, but chiefly in the temperate regions of the Old World. The species have square stems, opposite, aromatic leaves, and a stoloniferous creeping rootstock. The flowers are arranged in axillary clusters (cymes), which either form separate whorls or are crowded together into a terminal spike. The corolla is usually small and of a pale purple or pinkish colour; it has four nearly equal lobes, and encloses two long and two short stamens. Nearly three hundred intermediate forms have been named and described. Many of these varieties are permanent, in consequence of being propagated by stolons.
In Britain ten species are indigenous or naturalized. Mentha viridis, or spearmint, grows in marshy meadows, and is the species commonly used for culinary purposes; it is distinguished by its smooth, sessile leaves and lax tapering flower-spikes. It is probably a cultivated race of the next species, Mentha sylvestris, or horsemint, which chiefly differs from the above in its coarser habit and hairy leaves, which are silky beneath, and in its denser flower-spikes. This plant is supposed to be the mint of Scripture, as it is extensively cultivated in the East; it was one of the bitter herbs with which the paschal lamb was eaten. M. rotundifolia resembles the last in size and habit, but is distinguished by its rounded wrinkled leaves, which are shaggy beneath, and by its lanceolate bracts. The last two species usually grow on damp waste ground. M. aquatica grows in ditches, and is easily recognized by its rounded flower-spikes and stalked hairy leaves.
M. piperita, or peppermint, has stalked smooth leaves and an oblong obtuse terminal spike of flowers; it is cultivated for its volatile oil. M. pratensis belongs to a group which have the flowers arranged in axillary whorls and never in terminal spikes; it otherwise bears some resemblance to M. viridis. M. sativa grows by damp roadsides, and M. arvensis in cornfields; they are distinguished from M. pratensis by their hairy stalked leaves, which in M. arvensis are all equally large, but in M. sativa are much smaller towards the apex of the stem. M. Pulegium, commonly known as pennyroyal, more rarely as fleamint, has small oval obtuse leaves and flowers in axillary whorls, and is remarkable for its creeping habit and peculiar odour. It differs from all the mints above described in the throat of the calyx being closed with hairs. It is met with in damp places on grassy commons, and was formerly popular for medicinal purposes.
All the genus Mentha abound in a volatile oil, contained in resinous dots in the leaves and stems. The odour of the oil is similar in several species, but is not distinctive, the same odour occurring in varieties of distinct species. Thus the peppermint flavour is found in M. piperita, in M. incana, and in Chinese and Japanese varieties of M. arvensis. Other forms of the lastnamed species growing in Ceylon and Java have the flavour of the common garden mint, M. viridis, and the odour is found in M. sylvestris, M. rotundifolia and M. canadensis. A bergamot scent is met with in a variety of M. aquatica and in forms of other species. Most mints blossom in August.
The name mint is also applied to plants of other genera, Monarda punctata being called horsemint, Pycnanthemum linifolium mountain mint, and Nepeta cataria catmint.
