Hedeoma pulegioides. Pennyroyal.
Nat. Ord. — Lamiaceae. Sex. Syst. — Diandria Monogynia.
Description. — This is an indigenous annual plant, sometimes called Tick-weed, Squaw-mint, etc. The root is small, fibrous, branching, yellow, from which arises a pubescent stem from six to fifteen inches in hight, upright, somewhat angular, with numerous, erect, slender branches. The leaves are opposite, small, lanceolate-oblong or ovate, narrowed at the base, margin remotely serrate, rough, pubescent and prominently veined on the under surface, smooth above, and on short petioles. The flowers are very small, of a pale-blue color, on short pedicels, and arranged in axillary whorls, along the whole length of the branches. The calyx is striated and pubescent, bilabiate, the upper lip divided into two ciliated segments, the lower into three rounded lobes. The stamens and style are filiform. The seeds are four, oblong, contained in the persistent calyx, the mouth of which is closed by bristles of the lower lip.
History. This herb was placed by Linnaeus in the genus Melissa, and
afterward Cunila, from which it was separated by Persoon, and placed in the genus Hedeoma. It must not be confounded with the Mentha Pulegium, or European Pennyroyal. It is a well known plant, growing in dry, sterile situations, especially in calcareous soils, and blossoms from June to September and October, rendering the air fragrant for some distance around it. It is common to nearly all parts of the United States. It has a pleasant, aromatic smell, which, however, is very offensive to some persons, and a warm, pungent, mint-like taste. It imparts its virtues to boiling water by infusion; boiling destroys its activity by evaporating the volatile oil, on which its properties depend. The oil may be obtained by distillation with water, and is often employed, or its tincture, instead of the herb itself; it is of a light-yellow color, and specific gravity 0.948.
Properties and Uses. — Pennyroyal is a stimulant, diaphoretic, emmenagogue, and carminative. The warm infusion, used freely, will promote perspiration, restore suppressed lochia, and excite the menstrual discharge when recently checked ; it is often used by females for this last purpose, — a large draught being taken at bed-time, the feet having been previously bathed in warm water. A gill of brewer's yeast added to the draught is reputed a safe and certain abortive. The warm infusion may likewise be employed with advantage in the flatulent colic of children. The oil, or its tincture, is also administered as a carminative, and antiemetic, and has been of benefit in hysteria, hooping-cough, spasms, etc. It is likewise used as a rubefacient in rheumatism, and united with linseed oil, as an application to burns. Dose of the oil, from two to ten drops.
Off. Prep. — Decoctum Hedeomae ; Oleum Hedeomae.