Description

Key Characters:

Growth Form: Robust, erect to decumbent perennial herbs.

Stems: Stems 9–50 dm long, glabrous.

Roots:

Leaves: Leaves simple. Opposite. Blades ovate, oblong–ovate to oblong–lanceolate, 8–24 cm long, (1.6–)2.5–10.5 cm wide. Apex long-acuminate. Base broadly cuneate or rarely subcordate. Surfaces glabrous, often red–tinged or with red veins; upper surfaces somewhat glossy; lower surfaces pale, thin and membranous. Margins serrate, rarely dentate or serrate–dentate. Petioles 2.5–7.5 cm long, glabrous. Stipules absent.

Flowers: Flowers 6(–10) per verticillaster, in unbranched, bracteate, racemose inflorescences 15–45 cm long, usually developing only terminally on branch, but occasionally with an additional pair of lateral inflorescences immediately below, pedicels slender, 5–15 mm long, peduncles stouter than pedicels, (3–)5–10(–15) mm long, bracts narrowly ovate, 10–25 mm long, rarely ciliate, lowermost pair slightly larger, 20–30(–45) mm long. Calyx obconical, 4–8(–11) mm long, enlarging in fruit, veins inconspicuous, glabrous, usually 5-toothed, the teeth narrowly deltate, (1.5–)2–3 mm long, rarely ciliate, apex attenuate, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent. Corolla bilabiate, white, sometimes tinged reddish purple, variable in size, tube narrowly funnelform, usually curved, usually either 10–13 mm or 18–25 mm long, upper lobe 3–9 mm long, lower lobe 6–20 mm long, slightly folded to form a groove, margins somewhat undulate, apex emarginate or entire; nectary disk often present at base of ovary, annular or developed on anterior side only. Stamens 4, both pairs of similar length or upper pair slightly longer, ascending the upper corolla lip, included, aligned with the sinuses; filaments inserted near throat, usually pubescent; anthers dithecal, opening by longitudinal slits; anther sacs divaricate. Ovary superior, 2-carpellate, placentation basal-axile; ovules 1 per ovary lobe; style 1, included, arising between lobes, shortly 2-lobed, the lobes clavate; stigmatic only at apex, 1 lobe often rudimentary; stigmas 2.

Fruit: Nutlets 4–5 mm long; 1-seeded; dark green to black; drupaceous; exocarp fleshy; obovoid; margins slightly winged; obliquely attached at the connate base; spreading and exserted from calyx at maturity. Seeds with endosperm absent or scanty and oily.

Ploidy: 2n = 66*

Habitat: Occurring in mesic to wet forest.

Elevation Range: 275–1,190 m.