Description

Key Characters:

Growth Form: Scandent vines climbing to 1–2 m.

Stems: Stems quadrangular, glabrous or pubescent in grooves.

Roots:

Leaves: Leaves simple. Opposite. Blades ovate–lanceolate, 4.2–7.7(–12) cm long, 1.7–2.9(–3.5) cm wide. Apex acute. Base obtuse to cordate. Surfaces glabrous, blades subcoriaceous. Margins serrate to subentire. Petioles 5–15 mm long, glabrous or occasionally with scattered hairs. Stipules absent.

Flowers: Flowers 2–6 per verticillaster, axillary, occasionally raised on peduncles 4–8 mm long, pedicels 4–7 mm long, puberulent. Calyx radially symmetrical, narrowly campanulate, 8–15 mm long at anthesis, enlarging in fruit, glabrous, the teeth linear-lanceolate, 4.5–7 mm long, 1.5–2.5 mm wide at base, splitting longitudinally, usually persistent or sometimes only ventral 1/2 persistent. Corolla bilabiate, tube and lobes very dark maroon, hispid externally, glandular pubescent within, tube narrowly funnelform, straight, 10–12.5 mm long, upper lip 4–8.5 mm long, entire or 2-lobed, flat or concave, lower lip 2–4 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; ovules 1 per ovary lobe, placentation basal-axile; style 1, exserted, arising between lobes, usually cleft, diverging after anther dehiscence, shortly 2-lobed, the lobes subulate; stigmas 2.

Fruit: Nutlets 1-seeded drupaceous; bluish black at maturity; ca. 5 mm long; margins slightly winged; obliquely attached at base; included within calyx at maturity; exocarp fleshy; obovoid. Seeds with endosperm absent or scanty and oily.

Ploidy: 2n = 64*

Habitat: Occurring in diverse mesic forest.

Elevation Range: 750–1,100 m.