Description

Key Characters:

Growth Form: Erect subshrub when young, becoming scandent.

Stems: Stems up to 3–4 m long, short–hirsute throughout.

Roots:

Leaves: Leaves simple. Opposite. Blades narrowly to broadly ovate, sometimes broadly so, 12.5-20 cm long, 2.0-8.8 cm wide. Apex acuminate. Base truncate, broadly rounded or broadly cuneate. Surfaces spreading hirsute, the hairs primarily concentrated on the veins on the lower surface. the red coloration in the leaves occurs at least when plants are in sunny sites and apparently is less intense in shaded sites. Margins coarsely dentate or serrate-dentate. Veins red-tinged. Petioles reddish green, 3.2-5 cm long, moderately to densely hirsute, sometimes somewhat retrorsely so. Stipules absent.

Flowers: Flowers (4)6 per verticillaster, sometimes the terminal one with 8 flowers, in an open, unbranched, racemose inflorescence 18-34 cm long, apparently the stem resuming vegetative growth after flowering, pedicels 9-10 mm long, sometimes on a common peduncle up to 4 mm long, moderately to densely short-hirsute, bracts ovate, the lower ones 6-11 cm long, the upper ones 2.5-3 cm long. Flowers bisexual (perfect) or sometimes unisexual (and then plants gynodioecious or rarely dioecious), flowers not fragrant in the morning, but have a light fragrance at 5 pm suggesting moth pollination. Calyx campanulate, 8–12 mm long, enlarging in fruit, green, short-hirsute on both surfaces, the hairs spreading to somewhat antrorsely appressed, the lobes 4-7 mm long, widely spreading, the margins with 1-several coarse teeth, apex acute, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent. Corolla bilabiate, white, ca. 19–22 mm long, tube narrowly funnelform, usually curved, short-hirsute mostly on the upper side, upper lip 6-7 mm long, entire or 2-lobed, flat or concave, the lower lip 9-12 mm long, 3-lobed, lateral lobes ovate, slightly asymmetrical, lower lobe broadly ovate to suborbicular, 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 ca. 8-9 mm long; 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:

Habitat: Known from only the upper parts of three valleys; where it grows along watercourses and at bases of waterfalls.

Elevation Range: 680–1,040 m.