Spec. Plant. Willd. iii. 74. Cl. 14. Ord. 1. Didynamia Gymnospermia. Nat. ord. Labiatae. G. 1102. Corolla not quite equal, four-cleft; the broader segment emarginate. Stamens upright, distant.

* Spiked.

Sp. 7. M. viridis. Spearmint. Smith (spec. 3.), Flora Brit. 612. Med. Bot. 3d edit. 338. t. 121.

* * Capitate.

Sp.\3. M. Piperita. Peppermint. Smith (spec. 4.), Flora Brit. 613. Med. Bot. 3d edit. 336. t. 120. Eng. Bot. 461.

* * * Verticillate.

Sp.20. M. Pulegium. Pennyroyal. Smith (spec. 12.), Flora Brit. 624. Med. Bot. 3d edit. 342. t.122.

1. Mentha viridis.1

Officinal. Mentha viridis, Lond. Mentha viridis herba, Dub. Spearmint. Syn. Baume verte (F.), Frauenmurze ( G.), Menta Romana (/.), Menta ( S.).

This is an indigenous, perennial plant, growing in marshy places, and flowering in August. For medicinal purposes it is cultivated. The root is creeping; the stem quadrangular and foliaceous, rising about two feet in height, erect, smooth, and branching. The leaves are opposite, nearly sessile, lanceolate, about two inches and a half long, and an inch broad; of a deep green colour above, paler beneath, pointed, serrated, smooth, and sometimes a little hairy underneath: the flowers are supported on smooth, partial flower-stalks, verticillated, in long, pointed, panicled spikes; furnished with cetaceous, ciliated, lanceolate bractes, longer than the flowers: the calyx is cylindrical and furrowed, with five nearly regular teeth : the corolla funnel-shaped, tender, smooth, and of a purple colour: the stamens are varying in length, with roundish anthers: and the style, which is filiform, with a bifid divaricated stigma, rises from a four-cleft germen : the seeds are four, small, and generally abortive, owing to the viviparous nature of the roots.

Hippoeratis. Hajc species dignoscitur pcdicellis. semper glaberrimis. -Smith, Flor. Brit. 613.

For medicinal use, spearmint is generally cut just as the flowers appear; but for obtaining the essential oil, the flowering plant is preferred. It should be cut in very dry weather.

Qualities.-Spearmint has a strong aromatic odour, and a warm, slightly bitter taste; neither of which qualities is impaired by drying. Both alcohol and water extract its virtues.

Medical properties and uses.-Spearmint is stomachic and carminative. The infusion is serviceable in allaying sickness and vomiting in a weakened state of the stomach.

Officinal preparations.-Aqua Mentha viridis, L. D. Infusum Menthce comp., D. Oleum Menthae, viridis, L. D. Spir. Menthae viridis, L.

2. Mentha Piperita.

Officinal. Mentha Piperita, Lond. Menthae Piperitae herba, Edin. Mentha Piperita; herba, Dub. Peppermint.

Syn. Menthe poivree (F.), Pfeffermuizze (G), Peperminte (Dutch), Pepar-mynta (Swed.), Menta piperita (I.), Verbal nena de sapor de Pimienta (S.), Hortelaa apimentada (Port.).

Peppermint is an indigenous, perennial plant, growing in moist places, and flowering in August and September. It is generally cultivated for medicinal use, particularly about Mitcham in Surrey1, whence the London market is chiefly supplied. There are three varieties of peppermint, the first of which is the officinal plant The root is creeping: the stem quadrangular and channelled, nearly upright, and about two feet high, branching, purplish, and rather hairy, with the hairs bent backwards : the leaves are of a dark green colour, opposite, petiolate, ovate, rather pointed, serrated, the upper side smoother arid less pubescent than the under, which is paler, with white and purple veins: the flowers are in terminal spikes, solitary, almost capitate, interrupted beneath, with the lower whorl more remote, and on a foot-stalk: the, bractes are lanceolate and ciliated; the calyx is furrowed, tender, studded with glandular points; the base entirely naked, very smooth, and five-cleft, with the teeth of a blackish purple colour, and ciliated: the corolla is purple; and conceals within its tube the anthers, which are on short filaments; the germen is four-cleft, with a filiform style, longer than the corolla, and furnished with a bifid stigma.

1 Considerably more than one hundred acres of this herb are grown in the parish of Mitcham; but the greater part of the peppermint is made into a liqueur, which is sold as a dram in London.-Stevenson's Survey, pp. 377, 378.

Dr. Smith supposes that this plant was discovered by Doctor Eales; and on examining the Linnaean Herbarium, now in his possession, he found that the Mentha piperita, described by Linnasus, was not our officinal plant, but merely a variety of the M. hirsuta, with the odour of peppermint. It was, however, first described by Petiver. "The cultivators of the plant observe, that, to keep up its quality, the roots must be transplanted every three years; otherwise it degenerates into the flavour of spearmint."1 If the plant be cut in wet weather, it changes to black, and is little worth.

Qualities.-The odour of both the recent and dried plant is penetrating and grateful, in some degree resembling camphor; and the taste pungent, warm, glowing, and bitterish, followed by a sensation of coldness in the mouth. These qualities depertd on an essential oil and camphor. The oil can be obtained separate by distillation in water, is of a yellowish colour, and holds the camphor in solution. One pound of the recent plant should yield from f 3j. to f ss. of the oil.

Medical properties and uses.-Peppermint is tonic, antispasmodic, and carminative. It is chiefly used to allay nausea and griping, to relieve flatulent colic, and in hysteria; or, as a vehicle, to cover the nauseous taste of other medicines; but to many palates it is extremely disagreeable. It may be given under the form of watery infusion; but the distilled water and the essential oil are generally preferred.

Officinal preparations.-Aqua Menthae Piperitae, L. E. D. Oleum Menthae Piperita, L. E. D. Spiritus Menthae Piperita, L. E.

3. Mentha Pulegium.2

Officinal. Pulegium, Lond. Menthae Pulegii herba, Edin. Mentha Pulegium; herba, Dub. Pennyroyal.

Syn. Menthe-peuliot(.F.), Polymunze Polei (G. Dutch, Dan.), Puleja (Swed.), Poley (Pol), Puleggio (I.,> Poleo (S.), Poejo (Port.).

This is an indigenous, perennial plant, growing on heaths and in moist meadows, and flowering in September. Like the other mints, it is cultivated for medicinal purposes; and becomes more luxuriant and erect. The stem is obtusely quadrangular, trailing, branching, and somewhat hairy; the leaves are petiolate, small, obtuse, bluntly serrated, and in a small degree hairy underneath; the flowers, which are supported on stalks covered with short thick hairs, are in sessile whorls, numerous, and many-flowered, and without bractes: the calyx is of a purplish green colour, tender, furrowed, and covered with thick short hairs; five-cleft, with the teeth pointed, unequal, and ciliated: the corolla is twice the length of the calyx, purple, four-cleft, with the base white and externally villous: the stamens are erect, and longer than the corolla; and the germen similar to that of the former species.

1 Linnaan Transactions, v. 176.

Dioscoridis.

Qualities.-The odour is similar to that of spearmint, but less fragrant; the taste aromatic and pungent, with a slight flavour of camphor. These qualities reside in a very volatile essential oil, which rises in distillation with water.1

Medical properties and uses.-Pennyroyal was formerly regarded as emmenagogue, expectorant, and diaphoretic; and was in repute for promoting the uterine evacuation, and relieving hysteria, hooping-cough, and asthma; but it is now justly considered of no value, and seldom used in regular practice.

Officinal preparations.-Aqua Pulegii, L. E. D. Oleum Pulegii, L. D. Spiritus Pulegii, L.