Perennial herb with erect scrambling or trailing stems 0.2–1.2 m. tall radiating from a woody rootstock; stems glabrous, with 2 raised lines on each internode below the stipules. Leaf-blades elliptic-oblong to elliptic- or linear-lanceolate, 1.2–6.5 cm. long, 0.1–1.6 cm. wide, acute to tapering acuminate at the apex, cuneate to rounded at the base, scabridulous above particularly near the margins, glabrous beneath; petiole very short or not developed; stipule-sheath 1 mm. long, with 1–5 short fimbriae or colleters 0.2–0.5 mm. long, sometimes with bristly hairs. Flowers heterostylous, in lax terminal or pseudo-axillary lax dichasia often running together to form ample panicles; pedicels 0.2–1(–1.5) cm. long (up to 3 cm. in inflorescences reduced to 1 flower). Calyx-tube subglobose, 0.6–1 mm. long, glabrous; lobes triangular, 0.5–1 mm. long, keeled, glabrous or with ciliate margins. Corolla dark blue, blue-purple to deep violet; tube 3–4.5 mm. long, hairy inside; lobes elliptic or oblong, 1.8–3.2 mm. long, 0.8–1.5 mm. wide. Style 3 mm. long in short-styled flowers, 4.5 mm. long in long-styled flowers; stigma-lobes 1–1.3 mm. long. Capsule globose, 2–2.8 mm. tall, 2.2–2.5 mm. wide, glabrous, obscurely 8-ribbed, scarcely beaked, crowned by the calyx-lobes. Seeds brown, angular, ± 0.5 mm. long, hilum borne on one of the keels, reticulate.
