Description
Key Characters:
Growth Form:
Aromatic, tomentose perennial herbs.
Stems:
Stems procumbent to ascending, 1–4 dm long.
Roots:
Leaves:
Leaves simple.
Opposite.
Blades narrowly ovate to narrowly elliptic, 8–30 mm long, 0.4–12 mm wide.
Base attenuate.
Surfaces pubescent at least on lower surface.
Margins subentire or with up to 6 teeth on each side.
Sessile or subsessile.
Stipules absent.
Flowers:
Flowers small, in well-spaced verticillasters in the leaf axils, each flower +/- bracteolate.
Calyx actinomorphic, (2–)2.5–3 mm long, campanulate to cylindrical, 10-nerved, 5-toothed, the teeth ciliate, lower ones subulate, upper ones slightly shorter and wider, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent.
Corolla zygomorphic, slightly bilabiate, funnelform to campanulate, lilac, (4–)4.5–6 mm long, upper lip entire or emarginate, lower lip 3-lobed; nectary disk often present at base of ovary, annular or developed on anterior side only.
Stamens 4, exserted beyond to included in corolla tube; anther sacs parallel; anthers dithecal, opening by longitudinal slits.
Ovary superior, 2-carpellate, placentation basal-axile; ovules 1 per ovary lobe; style 1; stigmas 2.
Fruit:
Nutlets 4; 1-seeded; pale brown; ca. 0.7–0.8 mm long.
Seeds with endosperm absent or scanty and oily.
Ploidy:
2n = 10; 20; 30; 40–42; 46
Habitat:
Cultivated and escaping from gardens; usually in damp areas.
Elevation Range: