Perennial climbing plant with an edible tuberous root. A somewhat succulent but sometimes thin and herbaceous stem, glabrous or pubescent, ramified. Leaves from cordate to ovate, unifoliate, dentate or deeply lobed, 5 to 10 cm long, glabrous or rarely pubescent, acute to acuminate apex, mucronate. Cymose to cymose-umbellate inflorescences with few flowers; flowers with oblong sepals; campanulate corolla with lavender to purple-lavender-coloured limb and darker throat, white in some varieties.

Perennial herb or suffrutex from 1 to 3 m in height, with puberulent branches. Membranous leaves, 3 to 13 cm in length, opposite, lanceolate to elliptic lanceolate, serrate or subentire margin, pubescent to glabrous on both sides, with resinous spots. Verticillaster inflorescences in the axils of the upper leaves reduced, short or almost non-existent pedicels, forming interrupted spikes, paniculate, with 12 to 15 flowers; tubular calyx, 2 mm long; white to blue corolla, somewhat pubescent, 2 to 3 mm long. Fruits, 2 to 4 small ovoid-oblong nuts, 1.5 to 1.7 mm long.

Herbaceous creeping or erect, stems up to 3 m, slightly downy/hirsute. Ovate-oblong leaves of 2 to 4 cm in length and 1.2 to 1.5 cm in width, both pubescent surfaces with resinous spots, crenate-serrate margins, narrowly margined petioles.
Flowers in axillary heads, semiglobose, 1 cm in diameter, with a peduncle up to 2.5 cm; bracts ovate or elliptic, 4 to 6 mm, hirsute and ciliate; calyx 3 to 4 mm, teeth equal; corolla white or white-greenish, 4 to 5 mm; fruits, nuts 0.7 to 1 mm in length, glabrous.

Shrub of 1 to 4 m in height. Alternate leaves, ovate, sharp to acuminate in the apex, serrate. 5 to 7 bracteoles, linear. Campanulate calyx; white, red-purple, yellow or orange corolla, variable in size, very bright and colourful; staminal tube longer than petals. Oblong capsule almost 3 cm in diameter.