Description

Key Characters:

Growth Form: Aromatic, erect annual or short-lived perennial herbs up to 3 m tall.

Stems: Stems 4-angled, 5–20 dm long, many-branched, hirsute with gland dots.

Roots:

Leaves: Leaves simple. Opposite. Blades ovate to broadly obovate, 3–10 cm long, 2–6 cm wide. Apex subacute. Base rounded to truncate, often slightly oblique. Upper surfaces sparsely pilose; lower surfaces sparsely to moderately hirsute; young leaves often purple tinged, particularly on the margin. Margins irregularly serrulate. Petioles 0.5–3 cm long. Stipules absent.

Flowers: Flowers 2–5 in lax cymes, these arranged in axillary, pedunculate racemes. Calyx often dark purple, glandular, narrowly campanulate, 5–5.5 mm long, enlarging to 8–10 mm long in fruit, strongly ribbed, the teeth bristly, the mouth conspicuously ciliate. Corolla blue or bluish violet, 4–6 mm long, 2-lipped, lower lip saccate, mauve with dark purple lines at the base of the broad 2-lobed upper lip. Stamens 4; anthers dithecal, opening by longitudinal slits. Ovary superior, 2-carpellate, placentation basal-axile; ovules 1 per ovary lobe; style 1; stigmas 2.

Fruit: Nutlets dark brown; narrowly oblong; 1.2–1.5 mm long; faintly rugose; apex often emarginate.

Ploidy: 2n = 28; 30; 32

Habitat: sparingly naturalized in relatively dry; disturbed sites.

Elevation Range: 150–300 m.