Mentha pulegium L.
pennyroyal
Perennial with prostrate creeping and ascending stems to c. 30 cm long, hairy when aerial, glabrous when submerged. Lvs petiolate, sometimes shortly so; lamina of vegetative shoots usually 0.6-2 × 0.4-1 cm, ovate, elliptic to suborbicular, not rugose, entire or sparingly and shallowly toothed, usually glabrous when submerged, hairy and densely dotted with glands when aerial; base attenuate to rounded; apex rounded to acute. Lvs subtending the axillary verticels similar, but often smaller, hairy. Verticels axillary, spaced, with densely packed, shortly pedicellate fls. Calyx c. 3 mm long, campanulate, purple, hairy and dotted with glands outside, with prominent white hairy tuft in throat; teeth ± forming 2 lips, acuminate, ciliate, < tube at anthesis. Corolla 4-6 mm long, mauve, hairy outside, well exserted. Stamens usually exserted at anthesis. Nutlets 0.5-0.6 mm long, bluntly angled, oblong.
N.; S.; St.
Europe, N. Africa, Macaronesia 1883
Common to abundant in wet pastures, by rivers and lakesides, also in drier places, including bare lava and backs of sandy beaches.
FL Nov-May.
Pennyroyal is so abundant in some pastures that they appear completely purple from a distance when it is flowering. It is disliked by some farmers because the strong aroma can taint milk. However, it has been used for its oil and is occasionally cultivated for this.
