Description

Key Characters:

Growth Form: Scandent or decumbent vines, occasionally forming a dense ground cover.

Stems: Stems sharply or sometimes moderately 4–angled, glabrous or moderately to densely scabrous, hairs on stem ridges or occasionally restricted to nodes.

Roots:

Leaves: Leaves simple. Opposite. Blades broadly ovate, 1.9–6.5 cm long, 1.7–4.2 cm wide. Apex acute or obtuse. Base cordate. Surfaces glabrous or with scattered hairs; blades membranous. Margins crenate or rarely serrate. Petioles 0–3(–4) mm long, glabrous or hispid. Stipules absent.

Flowers: Flowers 2(–6) per verticillaster, axillary, pedicels 3–8 mm long, tomentose. Calyx bilabiate, narrowly campanulate, 7–15 mm long, enlarging in fruit, sparsely to moderately hispid, hairs concentrated near base of calyx, the teeth acute, (2–)3.5–8 mm long, 1.5–3 mm wide at base, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent. Corolla bilabiate, white, pink, or dark purple externally, cream within, densely tomentose distally externally, glabrous within, tube narrowly funnelform, straight or slightly falcate, 12–25 mm long, upper lip 3–9 mm long, entire or 2-lobed, flat or concave, lower lip 1.5–2 mm long, 3-lobed, the lobes flat or margins revolute, ovate, of similar size, distal portion of corolla sparsely to densely pubescent externally, the hairs simple or multicellular, occasionally glandular pubescent within, otherwise glabrous; 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, included within corolla or well–exserted beyond upper lip; filaments inserted near throat, pubescent; anthers dithecal; anther sacs divaricate, opening by longitudinal slits. Ovary superior, 2-carpellate, each carpel longitudinally divided, placentation basal-axile; ovules 1 per ovary lobe; style 1, exserted, arising between lobes, usually cleft, diverging after anther dehiscence, shortly 2-lobed, the lobes subulate; stigmas 2.

Fruit: Nutlets ca. 3–6 mm long; 1-seeded; drupaceous; black at maturity; margins slightly winged; obliquely attached at base; included within calyx at maturity; exocarp fleshy; obovoid. Seeds with endosperm absent or scanty and oily.

Ploidy:

Habitat: Occurring in mesic to occasionally wet forest.

Elevation Range: 900–1,700 m.