Perennial herbs with a pilose indumentum of simple hairs. Leaves undivided, entire to irregularly serrate, lower petiolate. Verticillasters c. 6-flowered congested to form a dense terminal ovoid-oblong terminal spike. Bracts large, ± imbricate. Flowers violet, purple or white, ± sessile. Calyx tubular-campanulate, bilabiate; upper lip 3-toothed; lower lip 2-toothed; throat glabrous; in fruit mouth ± closed. Corolla bilabiate; tube straight, widened above, pilose-squamate near base; lower lip 3-lobed with a dentate median lobe; upper lip galeate, cucullate entire. Stamens 4, included in upper lip of corolla or somewhat exserted, didynamous, anterior longer than posterior; filaments apically 2-armed, one sterile and subulate, the other bearing a 2-locular theca; thecae divering, glabrous. Style glabrous with 2 subequal branches. Nutlets ovoid to elliptic, basally cuneate with a small white caruncle, apically obtuse; smooth.

A small mainly European and Asiatic genus of about 7 species; 1 species in temperate areas of both hemispheres. Characteristic features are the terminal spike-like inflorescence and the apically divided staminal filaments.

Lower Taxon

• Prunella vulgaris L.