There are several kinds of Prunella, widely distributed, but this is the only one common in this country and is probably not native. It is abundant in dampish places, in the far West often staying green all winter, a perennial, sometimes hairy, from two inches to over a foot high. The leaves, often obscurely toothed, have leaf-stalks and the small flowers are crowded in a series of whorls, with purplish bracts and forming a spike or head. The calyx is two-lipped, with five teeth and often purplish, and the corolla is purple, pink, or occasionally white, with an arched upper lip, a spreading, three-lobed lower lip, and four stamens, under the upper lip of the corolla, the lower pair longer. This is usually not pretty, but in favorable situations in the West is often handsome, with brighter-colored, larger flowers. The name, often spelled Brunella, is said to be derived from an old German word for an affection of the throat, which this plant was supposed to cure. There is a picture in Mr. Mathews' Field Book.
There are many kinds of Stachys, widely distributed; herbs, often hairy, with a disagreeable smell; the calyx with five, nearly equal teeth; the corolla with a narrow tube, the upper lip erect, the lower lip spreading and three-lobed, the middle lobe longest; the stamens four, in pairs, usually under the upper lip of the corolla.