Description

Key Characters:

Growth Form: Annual or perhaps short-lived perennial herbs.

Stems: Stems ascending to erect, 5–10 dm long, conspicuously hispid and puberulent in lines.

Roots:

Leaves: Leaves simple. Opposite. Blades deltate–ovate, 2–7 cm long, 0.8–3 cm wide. Apex acute. Base truncate to subcordate. Upper surfaces moderately puberulent; lower surfaces pale, densely puberulent, becoming tomentose. Margins crenate–serrate, sometimes lower leaves long–ciliate. Petioles 0.5–2.3 cm long. Stipules absent.

Flowers: Flowers (1)3–6 in verticillasters, these arranged in terminal, racemose inflorescences, bracts lanceolate, 3–6 mm long, margins long-ciliate, caducous. Calyx bilabiate, tubular to campanulate, often tinged purple, 6-9 mm long, cleft nearly 1/2 its length, short hirtellous, 10–15–nerved, upper lip usually concave or arched, entire or 2-toothed, lower lip 2-toothed, sometimes the teeth and lips obsolete. Corolla scarlet, strongly bilabiate, tube straight or curved 13-17 mm long, upper lip 3.5-5 mm long, subgaleate, entire or 2-lobed, lower lip spreading, 3-lobed; nectary disk often present at base of ovary, annular or developed on anterior side only. Stamens 2, exserted ca. 3–4 mm beyond corolla tube, aligned with the sinuses; anthers dithecal, opening by longitudinal slits, with an elongate connective articulated near the center of the filament; anther sacs at each end, sometimes lower anther sac or entire lower arm of connective rudimentary. Ovary superior, 2-carpellate; ovules 1 per ovary lobe, placentation basal-axile; style 1; stigmas 2.

Fruit: Nutlets 4; 1-seeded; ca. 2.5 mm long. Seeds with endosperm absent or scanty and oily.

Ploidy: 2n = 20; 22

Habitat: Naturalized in low elevation; dry; disturbed habitats.

Elevation Range: 50–1,000 m.